AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON AUGUST 3, 2001

                                                           REGISTRATION NO. 333-
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                            ------------------------

                                    FORM S-3
                             REGISTRATION STATEMENT
                                     UNDER
                           THE SECURITIES ACT OF 1933

                            ------------------------

                                STEMCELLS, INC.
             (Exact name of registrant as specified in its charter)


                                                              
            DELAWARE
  (State or other Jurisdiction                  2836                           94-3078125
      of Incorporation or           (Primary Standard Industrial            (I.R.S. Employer
         Organization)              Classification Code Number)           Identification No.)


                            ------------------------

                               3155 PORTER DRIVE
                              PALO ALTO, CA 94304
                                 (650) 475-3100
  (Address, including zip code, and telephone number, including area code, of
                   Registrant's principal executive offices)

                         ------------------------------

                                IRIS BREST, ESQ.
                                STEMCELLS, INC.
                               3155 PORTER DRIVE
                              PALO ALTO, CA 94304
                                 (650) 475-3100
 (Name, address, including zip code, and telephone number, including area code,
                             of agent for service)

                         ------------------------------

                                   COPIES TO:
                            GEOFFREY B. DAVIS, ESQ.
                                  Ropes & Gray
                            One International Place
                          Boston, Massachusetts 02110
                                 (617) 951-7000
                              (617) 951-7050 (fax)

                           --------------------------

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC: As soon as
practicable after this Registration Statement becomes effective.

    If any of the securities being registered on this Form are to be offered on
a delayed or continuous basis pursuant to Rule 415 under the Securities Act of
1933, check the following box. /X/

    If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, check the following box and
list the Securities Act registration statement number of the earlier effective
registration statement for the same offering. / /

    If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

    If this Form is a post-effective amendment filed pursuant to Rule 462(d)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. / /

    If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. / /

                         ------------------------------

                        CALCULATION OF REGISTRATION FEE



                                                                    PROPOSED MAXIMUM     PROPOSED MAXIMUM
     TITLE OF EACH CLASS OF SECURITIES           AMOUNT TO BE      OFFERING PRICE PER   AGGREGATE OFFERING         AMOUNT OF
              TO BE REGISTERED                    REGISTERED            SHARE(1)             PRICE(1)          REGISTRATION FEE
                                                                                                  
Common Stock, par value $.01 per share......     1,900,000 shares        $4.275             $8,122,500              $2,031


(1) Estimated solely for the purpose of calculating the registration fee
    pursuant to Rule 457(c) of the Securities Act of 1933, based on the average
    of the high and low prices as reported on the Nasdaq National Market on
    August 2, 2001.

                         ------------------------------

    THE REGISTRANT HEREBY AMENDS THIS REGISTRATION STATEMENT ON SUCH DATE OR
DATES AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT SHALL
FILE A FURTHER AMENDMENT WHICH SPECIFICALLY STATES THAT THIS REGISTRATION
STATEMENT SHALL THEREAFTER BECOME EFFECTIVE IN ACCORDANCE WITH SECTION 8(a) OF
THE SECURITIES ACT OF 1933 OR UNTIL THE REGISTRATION STATEMENT SHALL BECOME
EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION 8(a),
MAY DETERMINE.

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--------------------------------------------------------------------------------

                  SUBJECT TO COMPLETION, DATED AUGUST 3, 2001
THE INFORMATION IN THIS PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. WE MAY
NOT SELL THESE SECURITIES UNTIL THE REGISTRATION STATEMENT FILED WITH THE
SECURITIES AND EXCHANGE COMMISSION IS EFFECTIVE. THIS PROSPECTUS IS NOT AN OFFER
TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER TO BUY THESE
SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.

PROSPECTUS

                                STEMCELLS, INC.
                        1,900,000 SHARES OF COMMON STOCK

                                ---------------

    The selling stockholder listed on page 49 of this prospectus or in an
accompanying supplement to this prospectus is offering to sell up to 1,900,000
shares of our common stock.

    Our common stock is listed on the Nasdaq National Market under the symbol
"STEM." The last reported sale price for our common stock on the Nasdaq National
Market on August 2, 2001 was $4.29 per share.

                            ------------------------

            THE SECURITIES OFFERED HEREBY INVOLVE A HIGH DEGREE OF RISK.
                    SEE "RISK FACTORS" BEGINNING ON PAGE 5.

                            ------------------------

    THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

               THE DATE OF THIS PROSPECTUS IS            , 2001.

                               TABLE OF CONTENTS



                                           PAGE
                                         --------
                                      
Prospectus Summary.....................       1
Risk Factors...........................       6
Forward-Looking Statements.............      12
Industry and Market Data...............      12
Use of Proceeds........................      12
Price Range of Common Stock............      13
Dividend Policy........................      13
Capitalization.........................      14
Selected Consolidated Financial Data...      15
Management's Discussion and Analysis of
  Financial Condition and Results of
  Operations...........................      16




                                           PAGE
                                         --------
                                      

Business...............................      23
Management.............................      42
Related Party Transactions.............      49
Selling Stockholder....................      51
Description of Capital Stock...........      52
Plan of Distribution...................      56
Legal Matters..........................      57
Experts................................      57
Where You Can Find More Information....      57
Incorporation of Documents by
  Reference............................      57
Index to Financial Statements..........     F-1


                                       i

                               PROSPECTUS SUMMARY

    THIS SUMMARY HIGHLIGHTS IMPORTANT INFORMATION REGARDING OUR BUSINESS AND
THIS OFFERING. BECAUSE THIS IS ONLY A SUMMARY, IT DOES NOT CONTAIN ALL THE
INFORMATION THAT MAY BE IMPORTANT TO YOU. YOU SHOULD READ THE ENTIRE PROSPECTUS
CAREFULLY, INCLUDING "RISK FACTORS" AND OUR FINANCIAL STATEMENTS AND RELATED
NOTES, BEFORE DECIDING TO INVEST IN OUR COMMON STOCK.

                                STEMCELLS, INC.

    We are engaged in research and development efforts focused on the
identification, isolation and expansion of stem cells as the underlying
technology for developing potential cell transplant therapies. Stem cells are
key cells in the body that produce all of the functional mature cell types found
in normal, healthy individuals. Our goal is to develop therapies that will use
stem cells to repopulate or repair tissues, such as those of the brain, pancreas
or liver, that have been damaged or lost as a result of disease or injury. All
of our programs are currently at the discovery or pre-clinical stage.

    Many diseases, such as Alzheimer's, Parkinson's and other degenerative
diseases of the brain or nervous system, involve the failure of organs that
cannot be transplanted. Other diseases, such as hepatitis and diabetes, involve
organs such as the liver or pancreas that can be transplanted, but there is a
very limited supply of those organs available for transplant. We estimate based
on information available to us from the Alzheimer's Association, the Centers for
Disease Control, the Family Caregiver's Alliance and the Spinal Cord Injury
Information Network, that these conditions affect more than 18 million people in
the United States and account for more than $150 billion annually in health care
costs.

    We believe that our stem cell technologies, if successfully developed, may
provide the basis for effective therapies for these and other conditions. Our
aim is to return patients to productive lives and significantly reduce the
substantial health care costs often associated with these diseases and
disorders. We have made significant progress toward developing stem cell
therapies for the nervous system by identifying and characterizing the human
central nervous system stem cell. We have also made significant advances in our
search for the stem cells of the pancreas and the liver by identifying novel
markers on the surface of cells so they can be isolated and tested to determine
whether they are stem cells.

    We have established our intellectual property position with respect to stem
cell therapies for each of these three areas--the central nervous system, the
pancreas and the liver--by patenting or seeking patent protection for our
discoveries and by entering into exclusive licensing arrangements. Our portfolio
of issued patents includes a method of culturing normal human neural stem cells
in our proprietary medium, and our published studies show that our cultured and
expanded cells give rise to all three major cell types of the central nervous
system. In addition, the Company recently announced the results of a new study
that showed that human brain stem cells can be successfully isolated with the
use of markers present on the surface of freshly obtained brain cells. We
believe this is the first reproducible process for isolating highly purified
populations of well-characterized normal human neural stem cells, and we have
applied for a composition of matter patent. We also have filed an improved
process patent for the growth and expansion of these purified normal human
neural cells.

    Historical Note: We were formerly known as CytoTherapeutics and were
incorporated in Delaware in 1988. We currently have one subsidiary, StemCells
California, Inc., a California corporation we acquired in September 1997. Until
mid-1999, we had programs in a different technology, encapsulated cell therapy,
as well as stem cell programs. In 1999, we embarked on a major restructuring of
our research and development operations and sold the encapsulated cell therapy
technology. We now focus exclusively on the discovery, development and
commercialization of our proprietary platform of stem cell technologies.

                                       1

                              RECENT DEVELOPMENTS

SALE OF MODEX SHARES

    On April 30, 2001, we sold 103,577 shares in Modex Therapeutics, Ltd., a
Swiss biotherapeutics company, for a net price of 87.30 Swiss Francs per share,
which converts to approximately $50.30, for total proceeds of approximately
$5,200,000, net of commissions and fees. We no longer hold any shares of Modex.
See "Business--Corporate Collaboration."

COMMON STOCK PURCHASE AGREEMENT RELATING TO EQUITY LINE

    On May 10, 2001, we entered into a common stock purchase agreement with
Sativum Investments Limited for the potential future issuance and sale of up to
$30,000,000 of our common stock, subject to restrictions and other obligations
that are described throughout this prospectus. We, at our sole discretion, may
draw down on this facility, sometimes termed an equity line, from time to time,
and Sativum is obligated to purchase shares of our common stock at a 6% discount
to a volume weighted average market price over the 20 trading days following the
drawdown notice. Our volume weighted average market price is calculated by
adding the total dollars traded in every transaction in a given trading day and
dividing that number by the total number of shares traded during that trading
day. We are limited with respect to how often we can exercise a drawdown and the
amount of each drawdown. In connection with the equity line, we issued a warrant
to purchase 250,000 shares of common stock to Sativum and warrants to purchase
an aggregate of 100,000 shares of common stock to placement agents, all at $2.38
per share. Our placement agents have exercised their warrants in full.

    We delivered a draw down notice to Sativum Investments Limited, dated as of
July 11, 2001, in connection with the common stock purchase agreement dated as
of May 10, 2001 evidencing an equity line facility between us and Sativum. In
the draw down notice, we notified Sativum that we are exercising our right to
sell up to $5,000,000 of our common stock to Sativum based on the formula in the
stock purchase agreement, during the 20 trading days beginning on July 12, 2001,
and ending on August 8, 2001. During the first 10 trading days, Sativum
purchased a total of 425,134 shares of our common stock at an average purchase
price of $5.88 per share, net of Sativum's discount of six percent. Our
placement agents, Pacific Crest Securities, Inc. and Granite Financial Group,
Inc. received $50,000 and $25,000, respectively, as placement fees in connection
with this draw down, resulting in net proceeds to us of $2,424,000 for the first
10 trading day settlement period after paying escrow fees.

    On July 2, 2001, the Securities and Exchange Commission declared effective a
registration statement with respect to up to 10,350,000 shares of our common
stock which we may issue pursuant to the common stock purchase agreement and
related warrants. We are not required to purchase any shares under the equity
line and cannot sell more than 3,922,606 shares pursuant to the agreement
without stockholder approval.

ISSUANCE OF NEW PATENTS

    On June 7, 2001, we announced the issuance to us of two new patents that
further our proprietary position in our neural and pancreatic research programs.
The first patent is a process patent that covers a novel method to separate
neural stem cells for growth in culture. The second patent covers a unique model
useful for identifying stem cells for the pancreas and liver. With these new
patents, we now own or have exclusive license to 25 issued U.S. patents in the
neural stem cell field, as well as fifteen U.S. applications, including two that
have been allowed, and pending foreign counterparts.

ISSUANCE OF SHARES AND WARRANTS TO MILLENNIUM PARTNERS

    On June 8, 2001, Millennium Partners, L.P. exercised an option to purchase
$2,000,000 of our common stock that it received in connection with an earlier
purchase of our common stock. At the closing on June 21, 2001, Millennium
purchased 457,750 shares of our common stock at $4.3692 per share. We received
$1,500,000 of the purchase price at the closing on June 21, 2001, and we will
receive

                                       2

the remaining $500,000 upon effectiveness of the registration statement of which
this prospectus forms a part. Millennium also received a warrant to purchase
50,352 shares of our common stock at a price per share of $4.7664. This warrant
is callable by us at any time at $7.944 per underlying share. In addition,
Millennium received an adjustable warrant similar to the adjustable warrant
issued to Millennium on August 3, 2000. See "Description of Capital
Stock--Warrants." We agreed to file a registration statement covering resales of
the issued shares and the shares underlying the warrants from time to time by
Millennium. See "Selling Stockholder."

                            ------------------------

    Our principal executive office is located at 3155 Porter Drive, Palo Alto,
California 94304 and our telephone number is (650) 475-3100. We maintain a
website on the Internet at WWW.STEMCELLSINC.COM. Our website, and the
information contained therein, is not a part of this prospectus.

                                       3

                                  THE OFFERING




                                            
Common stock offered.........................  Up to 1,900,000 shares of common stock
                                               offered for resale by the selling
                                               stockholder. See "Selling Stockholder." None
                                               of these shares will be offered by us.

Use of proceeds..............................  We will not receive any of the proceeds of
                                               the resale of shares covered by this
                                               prospectus.

Nasdaq National market symbol................  STEM


                                       4

                      SUMMARY CONSOLIDATED FINANCIAL DATA

    The following tables summarize the consolidated financial data for our
business. You should read this table together with "Management's Discussion and
Analysis of Financial Condition and Results of Operations" and our consolidated
financial statements and notes included elsewhere in this prospectus.



                                                                                                   THREE MONTHS ENDED
                                                                   YEAR ENDED DECEMBER 31,              MARCH 31,
                                                              ----------------------------------   -------------------
                                                                 1998         1999        2000       2000       2001
                                                              ----------   ----------   --------   --------   --------
                                                                    (IN THOUSANDS, EXCEPT INCOME PER SHARE DATA)
                                                                                               
CONSOLIDATED STATEMENT OF OPERATIONS DATA:
Revenue from collaborative agreements and grants............   $  8,803     $  5,022    $     74   $    --    $   100
Gain on sale of investment..................................         --           --       1,428        --      2,550
Research and development expenses...........................     17,659        9,984       5,979       907      1,644
ECT wind-down expenses......................................         --        6,048       3,327       234         --
Net income (loss)...........................................   $(12,628)    $(15,709)   $(11,125)  $(1,794)   $   269




                                                                  AS OF         AS OF
                                                              DECEMBER 31,    MARCH 31,
                                                                  2000           2001
                                                              -------------   ----------
                                                                    (IN THOUSANDS)
                                                                        
CONSOLIDATED BALANCE SHEET DATA:
Cash, cash equivalents and marketable securities............     $ 6,069        $ 4,499
Restricted investments......................................      16,356          8,413
Total assets................................................      29,795         21,507
Long-term debt, including capitalized leases................       2,605          2,521
Stockholders' equity........................................      22,982         15,462


    In July 1999 we began restructuring the company to focus solely on our stem
cell technology. As part of this restructuring we terminated all activities
related to our former encapsulated cell technology and we relocated our
headquarters from Rhode Island to California. The results shown for the year
ended December 31, 1999 and 2000 includes $6,047,806 and $3,327,360,
respectively, in expenses related to the restructuring. For more information on
this restructuring see "Business" and "Management's Discussion and Analysis of
Financial Condition and Results of Operations" and our consolidated financial
statements and notes included elsewhere in this prospectus.

    During 2000, in connection with our investment in Modex Therapeutics, Ltd.,
a Swiss biotechnology company that completed an initial public offering on
June 23, 2000, we realized a $1,427,686 gain and recognized an increase in value
related to our remaining holdings of $16,356,334 as of December 31, 2000. During
the three months ended March 31, 2001, we realized a gain of $2,550,000 in
connection with further sales of Modex shares. After a subsequent sale on
April 30, 2001, we no longer hold any shares of Modex. For more information on
Modex, see "Recent Developments" and "Management's Discussion and Analysis of
Financial Condition and Results of Operations" and our consolidated financial
statements and notes included elsewhere in this prospectus.

                                       5

                                  RISK FACTORS

    THE OFFERING INVOLVES A HIGH DEGREE OF RISK. YOU SHOULD CAREFULLY CONSIDER
THE RISKS DESCRIBED BELOW AND THE OTHER INFORMATION IN THIS PROSPECTUS BEFORE
MAKING AN INVESTMENT DECISION REGARDING STEMCELLS, INC.OUR BUSINESS, FINANCIAL
CONDITION OR RESULTS OF OPERATIONS COULD BE MATERIALLY ADVERSELY AFFECTED IF ANY
OF THESE RISKS ACTUALLY OCCUR. CONSEQUENTIALLY, THE TRADING PRICE OF OUR COMMON
STOCK COULD DECLINE, RESULTING IN THE LOSS OF ALL OR PART OF YOUR INVESTMENT.

    OUR TECHNOLOGY IS AT AN EARLY STAGE OF DISCOVERY AND DEVELOPMENT, AND WE MAY
FAIL TO DEVELOP ANY COMMERCIALLY ACCEPTABLE PRODUCTS.

    Our stem cell technology is at the early pre-clinical stage for the brain
stem cell and at the discovery phase for the liver and pancreas stem cells and
has not yet led to the development of any product. We may fail to discover the
stem cells we are seeking, to develop any products, to obtain regulatory
approvals, to enter clinical trials, or to commercialize any products. Any
product using stem cell technology may fail to:

    - survive and persist in the desired location;

    - provide the intended therapeutic benefits;

    - properly integrate into existing tissue in the desired manner; or

    - achieve therapeutic benefits equal to or better than the standard of
      treatment at the time of testing.

In addition, our products may cause undesirable side effects. Results of early
pre-clinical research may not be indicative of the results that will be obtained
in later stages of pre-clinical or clinical research. If regulatory authorities
do not approve our products, or if we fail to maintain regulatory compliance, we
would have limited ability to commercialize our products, and our business and
results of operations would be harmed. Furthermore, because stem cells are a new
form of therapy, the marketplace may not accept any products we may develop.

    If we do succeed in developing products, we will face many potential
obstacles such as the need to obtain regulatory approvals, and to develop or
obtain manufacturing, marketing and distribution capabilities. In addition, we
will face substantial additional risks such as product liability.

    WE HAVE PAYMENT OBLIGATIONS RESULTING FROM REAL PROPERTY OWNED OR LEASED BY
US IN RHODE ISLAND, WHICH DIVERTS FUNDING FROM OUR STEM CELL RESEARCH AND
DEVELOPMENT.

    Prior to our reorganization in 1999 and the consolidation of our business in
California, we carried out our encapsulated cell therapy programs in Lincoln,
Rhode Island, where we also had our administrative offices. Although we have
vacated the Rhode Island facilities, we remain obligated to make lease payments
and operating costs of approximately $1,200,000 per year for our former science
and administrative facility, which we have leased through June 30, 2013, and
debt service payments and operating costs of approximately $1,000,000 per year
for our former encapsulated cell therapy pilot manufacturing facility, which we
own. We are currently seeking to sublease the science and administrative
facility and to sell the pilot manufacturing facility, but may not be able to do
so. These continuing costs significantly reduce our cash resources and adversely
affect our ability to fund further development of our stem cell technology. In
March 2001, our landlord approved a sublease of part of the premises.

    WE MAY NEED BUT FAIL TO OBTAIN PARTNERS TO SUPPORT OUR STEM CELL DEVELOPMENT
EFFORTS AND TO COMMERCIALIZE OUR TECHNOLOGY.

    Equity and debt financings alone may not be sufficient to fund the cost of
developing our stem cell technologies, and we may need to rely on our ability to
reach partnering arrangements to provide financial support for our stem cell
discovery and development efforts. In addition, in order to

                                       6

successfully develop and commercialize our technology, we may need to enter into
a wide variety of arrangements with corporate sponsors, pharmaceutical
companies, universities, research groups and others. While we have engaged, and
expect to continue to engage, in discussions regarding such arrangements, we
have not reached any agreement, and we may fail to obtain any such agreement on
terms acceptable to us. Even if we enter into these arrangements, we may not be
able to satisfy our obligations under them or renew or replace them after their
original terms expire. Furthermore, these arrangements may require us to grant
certain rights to third parties, including exclusive marketing rights to one or
more products, may require us to issue securities to our collaborators or may
contain other terms that are burdensome to us. If any of our collaborators
terminates its relationship with us or fails to perform its obligations in a
timely manner, the development or commercialization of our technology and
potential products may be adversely affected.

    WE HAVE A HISTORY OF OPERATING LOSSES AND WE MAY FAIL TO OBTAIN REVENUES OR
BECOME PROFITABLE.

    We have incurred $130,229,646 in operating losses through March 31, 2001 and
expect to continue to incur substantial operating losses in the future in order
to conduct our research and development activities, and, if those activities are
successful, to fund clinical trials and other expenses. These expenses include
the cost of acquiring technology, product testing, acquiring regulatory
approvals, establishing production, marketing, sales and distribution programs
and administrative expenses. We have not earned any revenues from sales of any
product. All of our past revenues have been derived from, and any revenues we
may obtain for the foreseeable future are expected to be derived from,
cooperative agreements, research grants, investments and interest on invested
capital. We currently have no cooperative agreements and we have received only
two research grants for our stem cell technology, and we may not obtain any such
agreements or additional grants in the future or receive any revenues from them.

    IF WE ARE UNABLE TO PROTECT OUR PATENTS AND PROPRIETARY RIGHTS, OUR
BUSINESS, FINANCIAL CONDITION AND RESULTS OF OPERATION WILL BE HARMED.

    We own or license a number of patents and pending patent applications
covering human nerve stem cell cultures, central nervous system stem cell
cultures, neuroblast cultures, peripheral nervous system stem cell cultures, and
an animal model for liver failure. Patent protection for products such as those
we propose to develop is highly uncertain and involves complex and continually
evolving factual and legal questions. The governmental authorities that consider
patent applications can deny or significantly reduce the patent coverage
requested in an application before or after issuing the patent. Consequently, we
do not know whether any of our pending applications will result in the issuance
of patents, or if any existing or future patents will provide sufficient
protection or significant commercial advantage or if others will circumvent
these patents. We cannot be certain that we were the first to make the
inventions covered by each of our pending patent applications or that we were
the first to file patent applications for such inventions because patent
applications are secret until patents are issued in the United States or until
the applications are published in foreign countries, and because publication of
discoveries in the scientific or patent literature often lags behind actual
discoveries. Patents may not issue from our pending or future patent
applications or, if issued, may not be of commercial benefit to us, or may not
afford us adequate protection from competing products. In addition, third
parties may challenge our patents or governmental authorities may declare them
invalid. In the event that a third party has also filed a patent application
relating to inventions claimed in our patent applications, we may have to
participate in proceedings to determine priority of invention. This could result
in substantial uncertainties and cost for us, even if the eventual outcome is
favorable to us, and the outcome might not be favorable to us. Even if a patent
issues, a court could decide that the patent was issued invalidly.

    Proprietary trade secrets and unpatented know-how are also important to our
research and development activities. We cannot be certain that others will not
independently develop the same or

                                       7

similar technologies on their own or gain access to our trade secrets or
disclose such technology, or that we will be able to meaningfully protect our
trade secrets and unpatented know-how and keep them secret. We require our
employees, consultants, and significant scientific collaborators and sponsored
researchers to execute confidentiality agreements upon the commencement of an
employment or consulting relationship with us. These agreements may, however,
fail to provide meaningful protection or adequate remedies for us in the event
of unauthorized use, transfer or disclosure of such information or inventions.

    IF OTHERS ARE FIRST TO DISCOVER AND PATENT THE STEM CELLS WE ARE SEEKING TO
DISCOVER, WE COULD BE BLOCKED FROM FURTHER WORK ON THOSE STEM CELLS.

    Because the first person or entity to discover and obtain a valid patent to
a particular stem or progenitor cell may effectively block all others, it will
be important for us or our collaborators to be the first to discover any stem
cell that we are seeking to discover. Failure to be the first could prevent us
from commercializing all of our research and development affected by that
patent.

    WE MAY BE UNABLE TO OBTAIN NECESSARY LICENSES TO THIRD PARTY PATENTS AND
OTHER RIGHTS.

    A number of pharmaceutical, biotechnology and other companies, universities
and research institutions have filed patent applications or have received
patents relating to cell therapy, stem cells and other technologies potentially
relevant to or necessary for our expected products. We cannot predict which, if
any, of the applications will issue as patents. If third party patents or patent
applications contain claims infringed by our technology and these claims are
valid, we may be unable to obtain licenses to these patents at a reasonable
cost, if at all, and may also be unable to develop or obtain alternative
technology. If we are unable to obtain such licenses at a reasonable cost, our
business could be significantly harmed.

    We have obtained rights from universities and research institutions to
technologies, processes and compounds that we believe may be important to the
development of our products. Licensors may cancel our licenses or convert them
to non-exclusive licenses if we fail to use the relevant technology or otherwise
breach these agreements. Loss of these licenses could expose us to the risks of
third party patents and/or technology. We can give no assurance that any of
these licenses will provide effective protection against our competitors.

    WE COMPETE WITH COMPANIES THAT HAVE SIGNIFICANT ADVANTAGES OVER US.

    The market for therapeutic products that address degenerative diseases is
large and competition is intense. We expect competition to increase. We believe
that our most significant competitors will be fully integrated pharmaceutical
companies and more established biotechnology companies, such as Biogen, Inc. and
Genzyme, an Elan Corporation. These companies already produce or are developing
treatments for degenerative diseases that are not stem cell-based, and they have
significantly greater capital resources and expertise in research and
development, manufacturing, testing, obtaining regulatory approvals and
marketing than we do. Many of these potential competitors have significant
products approved or in development that could be competitive with our potential
products, and also operate large, well-funded research and development programs.
In addition, we expect to compete with smaller companies such as NeuralStem and
Layton Bioscience and with universities and other research institutions who are
developing treatments for degenerative diseases that are stem cell-based.

    Our competitors may succeed in developing technologies and products that are
more effective than the ones we are developing, or that would render our
technology obsolete or non-competitive.

    The relative speed with which we and our competitors can develop products,
complete the clinical testing and approval processes, and supply commercial
quantities of a product to market will affect our ability to gather market
acceptance and market share. With respect to clinical testing, competition may

                                       8

delay progress by limiting the number of clinical investigators and patients
available to test our potential products.

    DEVELOPMENT OF OUR TECHNOLOGY IS SUBJECT TO AND RESTRICTED BY EXTENSIVE
GOVERNMENT REGULATION.

    Our research and development efforts, as well as any future clinical trials,
and the manufacturing and marketing of any products we may develop, will be
subject to and restricted by extensive regulation by governmental authorities in
the United States and other countries. The process of obtaining U.S. Food and
Drug Administration and other necessary regulatory approvals is lengthy,
expensive and uncertain. We or our collaborators may fail to obtain the
necessary approvals to commence or continue clinical testing or to manufacture
or market our potential products in reasonable time frames, if at all. In
addition, the U.S. Congress and other legislative bodies may enact regulatory
reforms or restrictions on the development of new therapies that could adversely
affect the regulatory environment in which we operate or the development of any
products we may develop.

    We base our research and development on the use of human stem and progenitor
cells obtained from fetal tissue. The federal and state governments and other
jurisdictions impose restrictions on the use of fetal tissue. These restrictions
change from time to time and may become more onerous. Additionally, we may not
be able to identify or develop reliable sources for the cells necessary for our
potential products--that is, sources that follow all state and federal
guidelines for cell procurement. Further, we may not be able to obtain such
cells in the quantity or quality sufficient to satisfy the commercial
requirements of our potential products. As a result, we may be unable to develop
or produce our products in a profitable manner.

    We may apply for status under the Orphan Drug Act for some of our therapies
to gain a seven year period of marketing exclusivity for those therapies. The
U.S. Congress in the past has considered, and in the future again may consider,
legislation that would restrict the extent and duration of the market
exclusivity of an orphan drug. If enacted, such legislation could prevent us
from obtaining some or all of the benefits of the existing statute even if we
were to apply for and be granted orphan drug status with respect to a potential
product.

    WE DEPEND ON A LIMITED NUMBER OF KEY PERSONNEL.

    We are highly dependent on the principal members of our management and
scientific staff and some of our outside consultants, including the members of
our scientific advisory board, our chief executive officer, each of our vice
presidents and the directors of our neural stem cell and liver stem cell
programs. Although we have entered into employment agreements with some of these
individuals, they may terminate their agreements at any time. We currently have
outside consultants and interim personnel, rather than permanent employees, in
key management and scientific positions. Loss of services of any of these
individuals could have a material adverse effect on our operations because these
individuals possess management experience or specialized scientific skills that
we do not otherwise have and that we may not be able to replace. In addition,
our operations are dependent upon our ability to attract and retain additional
qualified scientific and management personnel. We may not be able to attract and
retain the personnel we need on acceptable terms given the competition for
experienced personnel among pharmaceutical, biotechnology and health care
companies, universities and research institutions. If we lose the services of
these key personnel or are unable to attract and retain additional qualified
personnel, we may have to delay, reduce or eliminate some or all of our research
and development programs.

    HEALTH CARE INSURERS AND OTHER ORGANIZATIONS MAY NOT PAY FOR OUR PRODUCTS OR
MAY IMPOSE LIMITS ON REIMBURSEMENTS.

    In both domestic and foreign markets, sales of potential products are likely
to depend in part upon the availability and amounts of reimbursement from third
party health care payor organizations, including government agencies, private
health care insurers and other health care payors, such as health

                                       9

maintenance organizations and self-insured employee plans. There is considerable
pressure to reduce the cost of therapeutic products, and government and other
third party payors are increasingly attempting to contain health care costs by
limiting both coverage and the level of reimbursement for new therapeutic
products, and by refusing, in some cases, to provide any coverage for uses of
approved products for disease indications for which the U.S. Food and Drug
Administration has not granted marketing approval. Significant uncertainty
exists as to the reimbursement status of newly approved health care products. We
can give no assurance that reimbursement will be provided by such payors at all
or without substantial delay, or, if such reimbursement is provided, that the
approved reimbursement amounts will be sufficient to enable us to sell products
we develop on a profitable basis. Changes in reimbursement policy could also
adversely affect the willingness of pharmaceutical companies to collaborate with
us on the development of our stem cell technology.

    In certain foreign markets, pricing or profitability of prescription
pharmaceuticals is subject to government control. We also expect that there will
continue to be a number of federal and state proposals to implement government
control over health care costs. Efforts at health care reform are likely to
continue in future legislative sessions. We do not know what legislative
proposals federal or state governments will adopt or what actions federal, state
or private payers for health care goods and services may take in response to
health care reform proposals or legislation. We cannot predict the effect
government control and other health care reforms may have on our business.

    WE HAVE LIMITED LIQUIDITY AND CAPITAL RESOURCES AND MAY NOT OBTAIN THE
SIGNIFICANT CAPITAL RESOURCES WE WILL NEED TO SUSTAIN OUR RESEARCH AND
DEVELOPMENT EFFORTS.

    We have limited liquidity and capital resources and must obtain substantial
additional capital to support our research and development programs, for
acquisition of technology and intellectual property rights, and, to the extent
we decide to undertake these activities ourselves, for pre-clinical and clinical
testing of our anticipated products, pursuit of regulatory approvals,
establishment of production capabilities, establishment of marketing and sales
capabilities and distribution channels, and general administrative expenses. If
we do not obtain the necessary capital resources, we may have to delay, reduce
or eliminate some or all of our research and development programs or license our
technology or any potential products to third parties rather than
commercializing them ourselves.

    If we are unable to draw down on our equity line or choose not to do so, we
intend to pursue our needed capital resources through equity and debt
financings, corporate alliances, grants and collaborative research arrangements.
See "Management's Discussion and Analysis of Financial Condition and Results of
Operation--Liquidity and Capital Resources." We may fail to obtain the necessary
capital resources from any such sources when needed or on terms acceptable to
us. Our ability to complete any such arrangements successfully will depend upon
market conditions and, more specifically, on continued progress in our research
and development efforts. We are prohibited from entering into other stand-by
equity based credit facilities during the term of the common stock purchase
agreement that governs our equity line.

    IF OUR COMMON STOCK PRICE DROPS SIGNIFICANTLY, WE MAY BE DELISTED FROM THE
NASDAQ NATIONAL MARKET, WHICH COULD ELIMINATE THE TRADING MARKET FOR OUR COMMON
STOCK.

    Our common stock is quoted on the Nasdaq National Market. In order to
continue to be included in the Nasdaq National Market, a company must meet
Nasdaq's maintenance criteria. The maintenance criteria most applicable to us
requires a minimum bid price of $1.00 per share, $4,000,000 in net tangible
assets and $5,000,000 market value of the public float. The public float
excludes shares held directly or indirectly by any of our officers, directors
and holders of 10% or more of our outstanding common stock. As of March 31,
2001, we had approximately $15.4 million of net tangible assets. As of May 24,
2001, the market value of our public float was approximately $71.6 million, and
the lowest bid price of our common stock since March 31, 2001 was $1.47. We
cannot assure you that we will continue to meet these listing criteria. The
issuance by us of shares of common stock to Sativum, or the

                                       10

subsequent resale by investors of those shares, in either case at a discount to
the market price, may cause the trading price of our common stock to fall to a
level below the Nasdaq minimum bid price requirement. Failure to meet these
maintenance criteria may result in the delisting of our common stock from the
Nasdaq National Market. If our common stock is delisted and in order to have our
common stock relisted on the Nasdaq National Market, we would be required to
meet the criteria for initial listing, which are more stringent than the
maintenance criteria. Accordingly, we cannot assure you that if we were delisted
we would be able to have our common stock relisted on the Nasdaq National
Market.

    If our common stock were delisted from the Nasdaq National Market, we would
not be able to draw down any additional funds on the equity line, and we also
may be required to pay damages to other holders of our common stock under
agreements we previously entered into with them in connection with equity
financings. Finally, if our common stock were removed from listing on the Nasdaq
National Market, it might become more difficult for us to raise funds through
the sale of our common stock or securities convertible into our common stock.

                                       11

                           FORWARD-LOOKING STATEMENTS

    This prospectus includes forward-looking statements. You can identify these
statements by forward-looking words such as "may," "will," "possibly," "expect,"
"anticipate," "project," "believe," "estimate" and "continue" or similar words.
You should read statements that contain these words carefully because they
discuss our future expectations, contain projections of our future results of
operations or of our financial condition, or state other "forward-looking"
information. We believe that it is important to communicate our future
expectations to our investors. However, there will be events in the future that
we have not been able to accurately predict or control and that may cause our
actual results to differ materially from those discussed. For example,
contaminations at our facilities, changes in the pharmaceutical or biotechnology
industries, competition and changes in government regulations or general
economic or market conditions could all have significant effects on our results.
These factors should be considered carefully and readers should not place undue
reliance on our forward-looking statements. Before you invest in our common
stock, you should be aware that the occurrence of the events described in the
"Risk Factors," "Management's Discussion and Analysis of Financial Condition and
Results of Operations" and "Business" sections and elsewhere in this prospectus
could harm our business, operating results and financial condition. All forward
looking statements attributable to us or persons acting on our behalf are
expressly qualified in their entirety by the cautionary statements and risk
factors contained throughout this prospectus.

                            INDUSTRY AND MARKET DATA

    In this prospectus, we rely on and refer to information and statistics
regarding disease occurrences, costs of treatment, biotechnology, and the market
sectors in which we may compete in the future. We obtained this information and
statistics from various third party sources, discussions with our consultants
and/or our own internal estimates. We believe that these sources and estimates
are reliable, but we have not independently verified them.

                                USE OF PROCEEDS

    We will not receive any of the proceeds from the resale of shares offered by
the selling stockholder under this prospectus.

                                       12

                          PRICE RANGE OF COMMON STOCK

    Our common stock is quoted on the Nasdaq National Market under the symbol
"STEM." The following table sets forth the high and low sale prices of our
common stock for the periods indicated on the Nasdaq National Market.



                                                          COMMON STOCK PRICE
                                                          -------------------
                                                            HIGH       LOW
                                                          --------   --------
                                                               
First Quarter 1999......................................   $ 1.78     $1.16
Second Quarter 1999.....................................   $ 1.37     $0.53
Third Quarter 1999......................................   $ 2.38     $0.69
Fourth Quarter 1999.....................................   $ 1.62     $1.00
First Quarter 2000......................................   $20.00     $1.38
Second Quarter 2000.....................................   $ 8.06     $2.00
Third Quarter 2000......................................   $11.67     $3.53
Fourth Quarter 2000.....................................   $ 6.75     $2.25
First Quarter 2001......................................   $ 3.75     $1.72
Second Quarter 2001.....................................   $ 6.15     $1.47


    There were approximately 287 record holders of our common stock as of
April 25, 2001. On August 2, 2001, the reported last sale price on the Nasdaq
National Market for our common stock was $4.29 per share.

                                DIVIDEND POLICY

    We have never declared or paid any cash dividends on our common stock. We
currently intend to retain any future earnings to fund the development and
growth of our business. We do not, therefore, anticipate paying any cash
dividends within the next five years. Any future determination to pay dividends
will be at the discretion of our board of directors and will be dependent on
then existing conditions, including our financial stability, results of
operations, contractual restrictions, capital requirements, business prospects
and other factors our board of directors deems relevant.

                                       13

                                 CAPITALIZATION

    The following table presents our consolidated capitalization as of
March 31, 2001. This table excludes:

    - 3,511,457 shares of common stock issuable upon the exercise of outstanding
      stock options and warrants as follows:

     a) as of March 31, 2001, 3,164,618 shares of common stock issuable upon the
        exercise of stock options pursuant to our stock option plans at a
        weighted average price of $4.11 per share.

     b) 171,839 shares of common stock issuable upon the exercise of warrants
        held by Millennium Partners, L.P. at a weighted average exercise price
        of $4.89 per share.

     c) 100,000 shares of common stock issued or issuable upon the exercise of
        warrants granted to May Davis Group, Inc. and four of its affiliates at
        an exercise price of $5.0375 per share.

     d) 75,000 shares of common stock issuable upon the exercise of warrants at
        $6.58 per share held by holders of our 6% cumulative convertible
        preferred stock.

    - 457,750 shares of common stock sold to Millennium on June 21, 2001, other
      shares issuable upon exercise of an adjustable warrant issued to
      Millennium on June 21, 2001, and additional shares issuable upon exercise
      of an adjustable warrant issued August 3, 2000.

    - 622,469 shares of common stock issued upon the exercise of a warrant held
      by Millennium at an exercise price of $0.01 per share.

    - additional shares of common stock issuable upon exercise of a warrant held
      by Millennium at an exercise price of $0.01 per share following a warrant
      adjustment date on July 27, 2001.

    - The right of the holders of our 6% cumulative convertible preferred stock
      to convert their shares of preferred stock into shares of common stock at
      $3.77 per share.

    - 100,000 shares of common stock issuable upon exercise of warrants held by
      Pacific Crest Securities, Inc. and Granite Financial Group, Inc. at an
      exercise price of $2.38.

    This table should be read in conjunction with "Management's Discussion and
Analysis of Financial Condition and Results of Operations" and our consolidated
financial statements and notes thereto included elsewhere in this prospectus.



                                                                  AS OF
                                                                MARCH 31,
                                                                  2001
                                                              -------------
                                                               (UNAUDITED)
                                                           
Stockholders' equity:
  Convertible Preferred Stock, par value $0.01 per share,
    1,000,000 shares authorized, 2,626 designated as 6%
    Cumulative Convertible Preferred Stock, 1,500 shares
    issued..................................................  $   1,500,000
  Common stock, par value $0.01 per share, 45,000,000 shares
    authorized, 21,458,211 shares issued....................        214,612
  Additional paid-in-capital................................    137,608,696
  Accumulated deficit.......................................   (130,229,646)
  Accumulated other comprehensive income....................      8,412,650
  Deferred compensation.....................................     (2,044,609)
                                                              -------------
    Total stockholders' equity..............................  $  15,461,703
                                                              =============


                                       14

                      SELECTED CONSOLIDATED FINANCIAL DATA

    The following selected consolidated financial data should be read in
conjunction with "Management's Discussion and Analysis of Financial Condition
and Results of Operations" and our consolidated financial statements and notes
to those statements and other financial information included elsewhere in this
prospectus.

    The consolidated historical financial data presented below as of
December 31, 1996, 1997, 1998, 1999 and 2000 and for the years then ended are
derived from our consolidated financial statements, which have been audited by
Ernst & Young LLP, our independent auditors. The selected consolidated financial
data as of March 31, 2001, and for the three months ended March 31, 2000 and
2001 are derived from our unaudited financial statements. In the opinion of our
management, the unaudited financial statements have been prepared on the same
basis as the audited consolidated financial statements and include all
adjustments (consisting only of normal recurring adjustments) necessary for a
fair presentation of the financial position and results of operations for such
periods. The selected consolidated financial data for the three months ended
March 31, 2001 are not necessarily indicative of the results that may be
expected for the year ended December 31, 2001 or any other future period.



                                                                                                  THREE MONTHS ENDED
                                                                                                       MARCH 31,
                                                        YEAR ENDED DECEMBER 31,                       (UNAUDITED)
                                          ----------------------------------------------------   ---------------------
                                            1996       1997       1998       1999       2000       2000        2001
                                          --------   --------   --------   --------   --------   ---------   ---------
                                                          (IN THOUSANDS, EXCEPT INCOME PER SHARE DATA)
                                                                                        
CONSOLIDATED STATEMENT OF OPERATIONS
  DATA:
Revenue from collaborative agreements
  and grants............................  $  7,104   $ 10,617   $  8,803   $  5,022   $     74    $    --    $    100
Gain on sale of investment..............        --         --         --         --      1,428         --       2,550
                                          --------   --------   --------   --------   --------    -------    --------
Research and development expenses.......    17,130     18,604     17,659      9,984      5,979        907       1,644
Acquired research and development.......        --      8,344         --         --         --         --          --
ECT wind-down and corporate relocation
  expenses..............................        --         --         --      6,048      3,327        234          --
Net income (loss).......................  $(13,759)  $(18,114)  $(12,628)  $(15,709)  $(11,125)   $(1,794)   $    269
Basic and diluted net income (loss) per
  share applicable to common
  stockholders before cumulative effect
  of a change in accounting principle...  $  (0.89)  $  (1.08)  $  (0.69)  $  (0.84)  $  (0.57)   $ (0.09)   $   0.01
Cumulative effect of a change in
  accounting principle..................        --         --         --         --      (0.01)        --          --
                                          --------   --------   --------   --------   --------    -------    --------
Net income (loss) per share applicable
  to common stockholders................  $  (0.89)  $  (1.08)  $  (0.69)  $  (0.84)  $  (0.58)   $ (0.09)   $   0.01
Shares used in computing basic net
  income (loss) per share...............    15,430     16,704     18,291     18,706     20,068     19,330      20,989
Shares used in computing diluted income
  (loss) per share......................    15,430     16,704     18,291     18,706     20,068     19,330      22,405




                                                                                                                AS OF
                                                                        AS OF DECEMBER 31,                    MARCH 31,
                                                       ----------------------------------------------------   ---------
                                                         1996       1997       1998       1999       2000       2001
                                                       --------   --------   --------   --------   --------   ---------
                                                                                (IN THOUSANDS)
                                                                                            
CONSOLIDATED BALANCE SHEET DATA:
Cash, cash equivalents and marketable securities.....  $42,607    $29,050    $17,386    $ 4,760    $ 6,069     $ 4,499
Restricted investments...............................       --         --         --         --     16,356       8,413
Total assets.........................................   58,397     44,301     32,866     15,781     29,795      21,507
Long-term debt, including capitalized leases.........    8,223      4,108      3,762      2,937      2,605       2,521
Redeemable common stock..............................    8,159      5,583      5,249      5,249         --          --
Stockholders' equity.................................   34,747     28,900     17,897      3,506     22,982      15,462


                                       15

                    MANAGEMENT'S DISCUSSION AND ANALYSIS OF
                 FINANCIAL CONDITION AND RESULTS OF OPERATIONS

    THE FOLLOWING DISCUSSION OF OUR FINANCIAL CONDITION AND RESULTS OF
OPERATIONS FOR THE THREE MONTHS ENDED MARCH 31, 2001 AND 2000 AND THE YEARS
ENDED DECEMBER 31, 2000, 1999 AND 1998 SHOULD BE READ IN CONJUNCTION WITH THE
"SELECTED CONSOLIDATED FINANCIAL DATA" SECTION OF THIS PROSPECTUS AND OUR
CONSOLIDATED FINANCIAL STATEMENTS AND NOTES TO THOSE STATEMENTS AND OTHER
FINANCIAL INFORMATION INCLUDED ELSEWHERE IN THIS PROSPECTUS. THE FORWARD-LOOKING
STATEMENTS IN THIS DISCUSSION REGARDING OUR EXPECTATIONS REGARDING OUR FUTURE
PERFORMANCE, LIQUIDITY AND CAPITAL RESOURCES AND OTHER NON-HISTORICAL STATEMENTS
IN THIS DISCUSSION INVOLVE NUMEROUS RISKS AND UNCERTAINTIES AS DESCRIBED IN THE
"RISK FACTORS" SECTION OF THIS PROSPECTUS. OUR ACTUAL RESULTS MAY DIFFER
MATERIALLY FROM THOSE CONTAINED IN ANY FORWARD-LOOKING STATEMENTS.

RESULTS OF OPERATIONS

    OVERVIEW

    Since our inception in 1988, we have been primarily engaged in research and
development of human therapeutic products. At the beginning of 1999, our
corporate headquarters, most of our employees, and the main focus of our
operations were primarily devoted to a different technology--encapsulated cell
therapy, or ECT. Since that time, we terminated a clinical trial of the ECT then
in progress, we wound down our other operations relating to the ECT, we
terminated the employment of those who worked on the ECT, we sold the ECT and we
relocated from Rhode Island to California. As a result of a restructuring in the
second half of 1999, our sole focus is now on our stem cell technology. The year
2000 was a year of transition, in which we completed the consolidation and
restructuring of our operations. Comparisons with results of operations prior to
2000 are correspondingly less meaningful than they may be under other
circumstances.

    We were known as CytoTherapeutics, Inc., until May 23, 2000, when we changed
our name to StemCells, Inc.

    We have not derived any revenues from the sale of any products, and we do
not expect to receive revenues from product sales for at least several years. We
have not commercialized any product and in order to do so we must, among other
things, substantially increase our research and development expenditures as
research and product development efforts accelerate and clinical trials are
initiated. We have incurred annual operating losses since inception and expect
to incur substantial operating losses in the future. As a result, we are
dependent upon external financing from equity and debt offerings and revenues
from collaborative research arrangements with corporate sponsors to finance our
operations. There are no such collaborative research arrangements at this time
and there can be no assurance that such or partnering revenues will be available
when needed or on terms acceptable to us.

    Our results of operations have varied significantly from year to year and
quarter to quarter and may vary significantly in the future due to the
occurrence of material, nonrecurring events, including without limitation the
receipt of one-time, nonrecurring licensing payments, sale of marketable
securities and the initiation or termination of research collaborations, in
addition to the winding-down of terminated research and development programs
referred to above.

    THREE MONTHS ENDED MARCH 31, 2001 AND 2000

    For the three months ended March 31, 2001, revenues from grants totaled
$100,000. There was no such revenue for the three months ended March 31, 2000.

    On January 9, 2001, we sold 22,616 Modex shares for a net price of 182.00
Swiss francs per share, which converts to $112.76 per share, for total proceeds
and a realized gain of $2,550,000.

    Research and development expenses totaled $1,644,257 for the three months
ended March 31, 2001, compared with $906,632 for the same period in 2000. The
increase of $737,625 or 81% from 2000 to 2001 was primarily attributable to the
related costs of an increase in personnel from 11 full time

                                       16

employees to 19 full time employees to facilitate the expansion of our research
programs and initiate development and the cost of leasing a larger facility.

    General and administrative expenses were $996,862 for the three months ended
March 31, 2001, compared with $657,714 for the same period in 2000. The increase
of $339,148, or 52%, from 2000 to 2001 was primarily attributable to the related
costs of an increase in personnel from 5 full time employees to 8 full time
employees, which included the hiring of senior management personnel as part of
the restructuring and consolidation of our operations in California and the cost
of leasing a larger facility.

    Wind-down expenses related to our ECT research, our Rhode Island operations
and the transfer of our headquarters to California for the three months ended
March 31, 2000 were $234,386. In December 2000, we created a reserve of
$1,780,578 related to the carrying costs for the Rhode Island facilities through
2001. At March 31, 2001 the reserve was $1,381,946.

    Interest income for the three months ended March 31, 2001 and 2000 was
$79,041 and $73,332 respectively. Interest expense of $64,460 for the three
months ended March 31, 2001 was booked against the wind-down reserve created in
2000 for the whole of 2001, as the expense was part of the bond payments related
to the Rhode Island facilities. Interest expense for the same period in 2000 was
$68,858. The decrease in 2001 was attributable to lower outstanding debt and
capital lease balances in 2001 compared to 2000.

    Other income for the three months ended March 31, 2001 was $180,389, which
was a refund from the Citizens Bank of Rhode Island for an overpayment of
property taxes in prior years.

    Net income for the three months ended March 31, 2001 was $268,541 or $0.01
per share, as compared to net loss of $1,794,258, or $0.09 per share, for the
comparable period in 2000. The decrease in net loss of $2,062,800 or 115% from
the same period in 2000 was primarily attributable to a realized gain of
$2,550,230 from the sale of a portion of our Modex investment, offset by an
increase in expenses attributable to an increase in personnel and the costs
associated with our move to a larger facility.

    YEARS ENDED DECEMBER 31, 2000, 1999 AND 1998

    Revenues totaled $74,000, $5,022,000 and $8,803,000 for the years ending
December 31, 2000, 1999 and 1998, respectively. Revenues for 2000 are from
Neurotech, S.A. in return for the assignment of our intellectual property assets
relating to Encapsulated Cell Technology. Revenues for 1999 and 1998 were from
collaborative agreements, earned primarily from a Development, Marketing and
License Agreement with AstraZeneca Group plc, which was signed in March 1995.
The decrease in revenues from 1998 to 1999 to 2000 resulted primarily from the
June 1999 termination of the Astra agreement.

    Research and development expenses totaled $5,979,000 in 2000, as compared to
$9,984,000 in 1999 and $17,659,000 in 1998. The decrease of $4,005,000, or 40%,
from 1999 to 2000 and the decrease of $7,675,000 or 43%, from 1998 to 1999, was
primarily attributable to the wind-down of research activities relating to our
encapsulated cell technology, precipitated by termination of the Astra
Agreement.

    General and administrative expenses were $3,361,000 in 2000, compared with
$4,927,000 in 1999 and $4,603,000 in 1998. The decrease of $1,566,000 or 32%,
from 1999 to 2000 was primarily attributable to the relocation of our
headquarters to a smaller facility as well as a reduction of personnel.

    Wind-down expenses related to our ECT research, our Rhode Island operations
and the transfer of our headquarters to California totaled $3,327,000 and
$6,048,000 for 2000 and 1999, respectively. No such expenses were incurred in
1998. 1999 expenses included accruals of approximately $1.6 million for employee
severance costs, $1.9 million in losses and reserves for the write-down of
related patents and fixed assets, $1.2 million for our costs of settlement of a
1989 funding agreement with RIPSAT,

                                       17

$700,000 of estimated additional carrying costs through June 30, 2000, and other
related expenses totaling $760,000.

    During 2000, we incurred approximately $290,000 of costs in excess of the
amounts accrued as of December 31, 1999 for the carrying costs, including lease
payments, property taxes and utilities, through the expected June 30, 2000
disposition of the Rhode Island facilities. During the third and fourth quarters
of 2000 we incurred additional $1.3 million in carrying costs for the Rhode
Island facilities, because we were unable to dispose of them as we had expected.
We have created a reserve of $1,780,000 related to the carrying costs for the
Rhode Island facilities through 2001. In February 2001, we subleased portions of
the facilities and are actively seeking to sublease, assign or sell our
remaining interests in the properties. However, there can be no assurance that
we will be able to dispose of these facilities in a reasonable time, if at all.

    Interest income for the years ended December 31, 2000, 1999 and 1998 totaled
$303,000, $564,000 and $1,254,000, respectively. The average cash and investment
balances were $5,668,000, $10,663,000 and $21,795,000 in 2000, 1999 and 1998,
respectively. The decrease in interest income from 1998 to 1999 to 2000 was
attributable to lower average balances.

    In 2000, interest expense was $273,000, compared to $335,000 in 1999 and
$472,000 in 1998. The decrease from 1998 to 1999 to 2000 was attributable to
lower outstanding debt and capital lease balances.

    During the second quarter 2000 we realized a $1,427,000 gain in connection
with the sale of a portion of our investment in Modex. Modex
Therapeutics, Ltd., a Swiss biotechnology company that completed an initial
public offering on June 23, 2000, and is publicly traded on the Swiss Neue
Market exchange.

    The net loss in 2000, 1999 and 1998 was $11,125,000, $15,709,000, and
$12,628,000, respectively. The loss per share was $0.58, $.84 and $.69 in 2000,
1999 and 1998, respectively. The decrease from 1999 to 2000 is primarily
attributable to the wind-down of our encapsulated cell technology research and
our Rhode Island operations and offset by the elimination of revenue from the
Astra Agreement. The increase from 1998 to 1999 is primarily attributable to the
elimination of revenue from the Astra Agreement, which was terminated in
June 1999, as well as expenses related to the wind-down of our encapsulated cell
technology research and our other Rhode Island operations, the transfer of our
corporate headquarters to California and an accrual for the our estimate of the
costs of settlement of a funding agreement with RIPSAT.

LIQUIDITY AND CAPITAL RESOURCES

    Since our inception, we have financed our operations through the sale of our
common and preferred stock, the issuance of long-term debt and capitalized lease
obligations, revenues from collaborative agreements, research grants, sales of
marketable securities and interest income.

    We had unrestricted cash and cash equivalents totaling $4,499,000 at
March 31, 2001. Cash equivalents are invested in money market funds.

    Our liquidity and capital resources were, in the past, significantly
affected by our relationships with corporate partners, which were related to our
former encapsulated cell technology, or ECT. These relationships are now
terminated, and we have not yet established corporate partnerships with respect
to our stem cell technology.

    In the third quarter of 1999, we announced restructuring plans to wind down
operations relating to our ECT and to focus our resources on the research and
development of our platform of proprietary stem cell technologies. We terminated
approximately 68 full time employees and, in October 1999, relocated our
corporate headquarters to California. As part of our restructuring of operations
and relocation of corporate headquarters to California, we identified a
significant amount of excess fixed

                                       18

assets. In December 1999, we completed the disposition of those excess fixed
assets, from which we received more than $746,000.

    On December 30, 1999 we sold our ECT and assigned our intellectual property
assets in it to Neurotech S.A. for a payment of $3,000,000, royalties on future
product sales, and a portion of certain Neurotech revenues from third parties.
In addition, we retained certain non-exclusive rights to use ECT in combination
with our proprietary stem cell technologies and in the field of vaccines for
prevention and treatment of infectious diseases.

    In July 1999, as a result of our decision to close our Rhode Island
facilities, the Rhode Island Partnership for Science and Technology, or RIPSAT,
alleged that we were in default under a June, 1989 Funding Agreement, and
demanded payment of approximately $2.6 million. While we believe we were not in
default under the Funding Agreement, we deemed it best to resolve the dispute
without litigation and, on March 3, 2000, entered into a settlement agreement
with RIPSAT, the Rhode Island Industrial Recreational Building Authority, or
IRBA, and the Rhode Island Industrial Facilities Corporation, or RIIFC. We
agreed to pay RIPSAT $1,172,000 in full satisfaction of all of our obligations
to them under the Funding Agreement. At the same time, IRBA agreed to return to
us the full amount of our debt service reserve, comprising approximately
$610,000 of principal and interest, relating to the bonds we had with IRBA and
RIIFC. The $610,000 debt service reserve was transferred directly to RIPSAT,
leaving the remainder of approximately $562,000 to be paid by us. We made this
payment in March of 2000.

    Our liquidity and capital resources could have also been affected by a claim
by Genentech, Inc., arising out of the their collaborative development and
licensing agreement with us relating to the development of products for the
treatment of Parkinson's disease; however, the claim was resolved with no effect
on our resources. On May 21, 1998, Genentech exercised its right to terminate
the Parkinson's collaboration and demanded that we redeem, for approximately
$3,100,000, certain shares of our redeemable Common Stock held by Genentech.
Genentech's claim was based on provisions in the agreement requiring us to
redeem, at the price of $10.01 per share, the shares representing the difference
between the funds invested by Genentech to acquire such stock and the amount
expended by us on the terminated program less an additional $1,000,000. In
March 2000, we entered into a Settlement Agreement with Genentech under which
Genentech released us from any obligation to redeem any shares of our Common
Stock held by Genentech, without cost to us. Accordingly, the $5.2 million of
redeemable common stock shown as a liability in our December 31, 1999 balance
sheet was transferred to equity in March, 2000 without any impact on our
liquidity and capital resources. We and Genentech also agreed that all
collaborations between us were terminated, and that neither of us had any rights
to the intellectual property of the other.

    We continue to have outstanding obligations in regard to our former
facilities in Lincoln, Rhode Island, including lease payments and operating
costs of approximately $1,200,000 per year associated with our former research
laboratory and corporate headquarters building, and debt service payments and
operating costs of approximately $1,000,000 per year with respect to our pilot
manufacturing and cell processing facility. We are actively seeking to sublease,
assign or sell our interests in these facilities. Failure to do so within a
reasonable period of time will have a material adverse effect on our liquidity
and capital resources.

    CONVERTIBLE PREFERRED STOCK

    On April 13, 2000, we sold 1,500 shares of our 6% cumulative convertible
preferred stock plus warrants for a total of 75,000 shares of our common stock
to two members of our Board of Directors for $1,500,000, on terms more favorable
to us than we were able to obtain from outside investors. The face value of the
shares of preferred stock is convertible at the option of the holders into
common stock at $3.77 per share. The holders of the preferred stock have
liquidation rights equal to their original investments plus accrued but unpaid
dividends. Any unconverted preferred stock will be

                                       19

converted to common stock, at the applicable conversion price, on April 13,
2002. The warrants expire on April 13, 2005.

    MILLENNIUM PARTNERS

    On August 3, 2000, we completed a $4 million common stock financing
transaction with Millennium Partners, LP, or the Fund, an investment fund with
more than $1 billion in assets under management. The Fund purchased our common
stock at $4.33 per share. The Fund is entitled, pursuant to an adjustable
warrant issued on August 3, 2000 in connection with the sale of common stock to
the Fund, to purchase additional shares of common stock for $0.01 per share. The
adjustments to the adjustable warrant are calculated on eight dates beginning
six months from the closing and every three months thereafter. The number of
additional shares the Fund may be entitled to on each date will be based on the
number of shares of common stock the Fund continues to hold on each date and the
market price of our common stock over a period prior to each date. We have the
right, under certain circumstances, to cap the number of additional shares by
purchasing part of the entitlement from the Fund. On January 27, 2001, the
Fund's adjustable warrant became exercisable for 463,369 shares of our common
stock, and the Fund purchased all of those shares on March 30, 2001, for $4,634.
On April 27, 2001, the Fund's adjustable warrant became exercisable for an
additional 622,469 shares of our common stock, and the Fund purchased all of
those shares on July 19, 2001 for $6,225. The Fund also received on August 3,
2000 a warrant to purchase up to 101,587 shares of common stock at $4.725 per
share. This warrant is callable by us at $7.875 per underlying share.

    In addition, the Fund was granted an option for twelve months to purchase up
to $3 million of additional common stock. On August 23, 2000 the Fund exercised
$1,000,000 of its option to purchase additional common stock at $5.53 per share.
The Fund paid $750,000 of the purchase price in connection with the closing on
August 30, 2000, and paid the remaining $250,000 upon effectiveness of a
registration statement covering the shares owned by the Fund. At the closing on
August 30, 2000, we issued to the Fund an adjustable warrant similar to the one
issued on August 3, 2000. This adjustable warrant was canceled by agreement
between us and the Fund on November 1, 2000. The Fund also received on
August 23, 2000 a warrant to purchase up to 19,900 shares of common stock at
$6.03 per share. This warrant is callable by us at any time at $10.05 per
underlying share.

    On June 8, 2001, the Fund exercised its remaining option to purchase
$2 million of our common stock. At the closing on June 21, 2001, the Fund
purchased 457,750 shares of our common stock at $4.3692 per share. The Fund paid
$1,500,000 of the purchase price at the closing and will pay the remainder upon
effectiveness of the registration statement of which this prospectus forms a
part. In connection with the closing, the Fund received an adjustable warrant
similar to the adjustable warrant issued on August 3, 2000. The Fund also
received a warrant to purchase 50,352 shares of our common stock at a price per
share of $4.7664. This warrant is callable by us at any time at $7.944 per
underlying share.

    MODEX

    We have sold all of our shares of Modex Therapeutics, Ltd. Our final sale of
Modex shares occurred on April 30, 2001, when we realized a gain of $5,232,168
net of commissions and other fees. All other sales occurred prior to March 31,
2001. In addition, on April 30, 2001, we sold Modex our rights to future
payments under the agreement between us and Neurotech S.A. for $300,000.

    EQUITY LINE

    On May 10, 2001, we entered into a common stock purchase agreement with
Sativum Investments Limited for the potential future issuance and sale of up to
$30,000,000 of our common stock, subject to restrictions and other obligations
that are described throughout this prospectus. We, at our sole discretion, may
draw down on this facility, sometimes termed an equity line, from time to time,
and Sativum is obligated to purchase shares of our common stock at a 6% discount
to a volume weighted

                                       20

average market price over the 20 trading days following the drawdown notice. We
are limited with respect to how often we can exercise a drawdown and the amount
of each drawdown. In connection with the equity line, we issued a warrant to
purchase 250,000 shares of common stock to Sativum and warrants to purchase an
aggregate of 100,000 shares of common stock to placement agents, all at $2.38
per share. Our placement agents, Pacific Crest Securities, Inc., and Granite
Financial Group, Inc., have exercised their warrants in full.

    We delivered a draw down notice to Sativum Investments Limited, dated as of
July 11, 2001, in connection with the common stock purchase agreement dated as
of May 10, 2001 evidencing an equity line facility between us and Sativum. In
the draw down notice, we notified Sativum that we are exercising our right to
sell up to $5,000,000 of our common stock to Sativum based on the formula in the
stock purchase agreement, during the 20 trading days beginning on July 12, 2001,
and ending on August 8, 2001. During the first 10 trading days, Sativum
purchased a total of 425,134 shares of our common stock at an average purchase
price of $5.88 per share, net of Sativum's discount of six percent. Our
placement agents, Pacific Crest Securities, Inc. and Granite Financial Group,
Inc. received $50,000 and $25,000, respectively, as placement fees in connection
with this draw down, resulting in net proceeds to us of $2,424,000 for the first
10 trading day settlement period after paying escrow fees.

    We have limited liquidity and capital resources and must obtain significant
additional capital resources in the future in order to sustain our product
development efforts. Substantial additional funds will be required to support
our research and development programs, for acquisition of technologies and
intellectual property rights, for preclinical and clinical testing of our
anticipated products, pursuit of regulatory approvals, acquisition of capital
equipment, laboratory and office facilities, establishment of production
capabilities and for general and administrative expenses. Our ability to obtain
additional capital will be substantially dependent on our ability to obtain
partnering support for our stem cell technology. Failure to do so will have a
material effect on our liquidity and capital resources. Until our operations
generate significant revenues from product sales, we must rely on cash reserves
and proceeds from equity and debt offerings, proceeds from the transfer or sale
of our intellectual property rights, equipment, facilities or investments,
government grants and funding from collaborative arrangements, if obtainable, to
fund our operations.

    We may, but are not required to, draw down on the equity line from time to
time as necessary and possible under the terms of the facility. We also intend
to pursue opportunities to obtain additional financing in the future through
grants and collaborative research arrangements. We are permitted under the terms
of the equity line to pursue unrelated debt and equity financing other than
other stand-by equity based credit facilities. The source, timing and
availability of any future financing will depend principally upon market
conditions, interest rates and, more specifically, on our progress in our
exploratory, preclinical and future clinical development programs. Lack of
necessary funds may require us to delay, reduce or eliminate some or all of our
research and product development programs or to license our potential products
or technologies to third parties. Funding may not be available when needed--at
all, or on terms acceptable to us.

    While our cash requirements may vary, as noted above, we currently expect
that our existing capital resources, including income earned on invested
capital, will be sufficient to fund our operations through December 2001. Our
cash requirements may vary, however, depending on numerous factors. If for some
reason we are not able to drawdown on the equity line, lack of necessary funds
may require us to delay, scale back or eliminate some or all of our research and
product development programs and/or our capital expenditures or to license our
potential products or technologies to third parties.

RECENT ACCOUNTING PRONOUNCEMENT

    In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
"Accounting for Derivative Instruments and Hedging Activities" (SFAS 133). The
statement requires us to recognize all derivatives on the balance sheet at fair
value. Derivatives that are not hedges must be adjusted to fair

                                       21

value through income. If the derivative is a hedge, depending on the nature of
the hedge, changes in fair value of derivatives are either offset against the
change in fair value of assets, liabilities, or firm commitments through
earnings or recognized in other comprehensive income until the hedged item is
recognized in earnings. Because we had no derivative instruments and do not
currently engage in hedging activities, the adoption of Statement No. 133 on
January 1, 2001 had no impact on our results of operations or financial
position.

                                       22

                                    BUSINESS

OVERVIEW

    We are engaged in research aimed at the development of therapies that would
use stem and progenitor cells derived from fetal or adult sources to treat, and
possibly cure, human diseases and injuries such as Parkinson's disease,
hepatitis, diabetes, and spinal cord injuries. The body uses certain key cells
known as stem cells to produce all the functional mature cell types found in
normal organs of healthy individuals. Progenitor cells are cells that have
already developed from the stem cells, but can still produce one or more types
of mature cells within an organ.

    Many diseases, such as Alzheimer's, Parkinson's, and other degenerative
diseases of the brain or nervous system, involve the failure of organs that
cannot be transplanted. Other diseases, such as hepatitis and diabetes, involve
organs such as the liver or pancreas that can be transplanted, but there is a
very limited supply of those organs available for transplant. We estimate, based
on information available to us from the Alzheimer's Association, the Centers for
Disease Control, the Family Caregiver's Alliance and the Spinal Cord Injury
Information Network, that these conditions affect more than 18 million people in
the United States and account for more than $150 billion annually in health care
costs.

    Our proposed therapies are based on the transplanting of healthy human stem
and progenitor cells to repair or replace central nervous system, pancreas or
liver tissue that has been damaged or lost as a result of disease or injury,
potentially returning patients to productive lives and significantly reducing
health care costs. We believe that we have achieved significant progress in
research regarding stem cells of the central nervous system through the advances
we have made in the isolation, purification and transplantation of central
nervous system stem and progenitor cells. We have also made advances in our
research programs to discover the stem cells of the pancreas and of the liver.
We have established an intellectual property position in all three areas of our
stem cell research--the central nervous system, the pancreas and the liver--by
patenting our discoveries and entering into exclusive licensing arrangements. We
believe that, if successfully developed, our platform of stem cell technologies
may create the basis for therapies that would address a number of conditions
with significant unmet medical needs.

    We were formerly known as CytoTherapeutics, Inc. Until mid-1990 we had
programs in a different technology, encapsulated cell therapy, as well as stem
cell programs. We now focus exclusively on the discovery, development and
commercialization of our proprietary platform of stem cell technologies.
Effective May 2000 we changed our name to StemCells, Inc.

CELL THERAPY BACKGROUND

ROLE OF CELLS IN HUMAN HEALTH AND TRADITIONAL THERAPIES

    Cells maintain normal physiological function in healthy individuals by
secreting or metabolizing substances that are essential to life. When cells are
damaged or destroyed, they no longer produce, metabolize or accurately regulate
these substances. Impaired cellular function is associated with the progressive
decline common to many degenerative diseases of the nervous system, such as
Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis.
Recent advances in medical science have identified cell loss or impaired
cellular function as leading causes of degenerative diseases. Biotechnology
advances have led to the identification of some of the specific substances or
proteins that are deficient. While administering these substances or proteins as
medication does overcome some of the limitations of traditional pharmaceuticals,
such as lack of specificity, there is no existing technology that can deliver
them to the precise sites of action and in the appropriate physiological
quantities or for the duration required to cure the degenerative condition.
Cells, however, do this naturally. As a result, investigators have considered
replacing failing cells that are no longer producing

                                       23

the needed substances or proteins by implanting stem or progenitor cells capable
of regenerating the cell that the degenerative condition has damaged or
destroyed. Where there has been irreversible tissue damage or organ failure,
transplantation of stem cells offers the possibility of generating new and
healthy tissue, thus potentially restoring the organ function and the patient's
health.

THE POTENTIAL OF OUR STEM CELL-BASED THERAPY

    We believe that, if successfully developed, stem cell-based therapy--the use
of stem or progenitor cells to treat diseases--has the potential to provide a
broad therapeutic approach comparable in importance to traditional
pharmaceuticals and genetically engineered biologics.

    Stem cells are rare and only available in limited supply, whether from the
patients themselves or from donors. Cells obtained from the same person who will
receive them may be abnormal if the patient is ill or the tissue is contaminated
with disease-causing cells. Also, obtaining the cells often requires significant
surgical procedures. The challenge, therefore, has been three-fold:

    - to identify the stem cells;

    - to create techniques and processes that we can use to expand these rare
      cells in sufficient quantities for effective transplants; and

    - to establish a bank of normal human stem or progenitor cells that we can
      use for transplantation into individuals whose own cells are not suitable
      because of disease or other reasons.

    We have developed and demonstrated a process, based on a proprietary IN
VITRO culture system in chemically defined media, that reproducibly grows normal
human central nervous system, or CNS, stem and progenitor cells. We believe this
is the first reproducible process for growing normal human CNS stem cells. More
recently, we have discovered markers on the cell surface that identify the human
CNS stem cells. This allows us to purify them and eliminate other unwanted cell
types. Together, these discoveries enable us to select normal human CNS stem
cells and to expand them in culture to produce a large number of pure stem
cells.

    Because these cells have not been genetically modified, they may be
especially suitable for transplantation and may provide a safer and more
effective alternative to therapies that are based on cells derived from cancer
cells, cells modified by a cancer gene, an unpurified mixture of many different
cell types, or animal derived cells. We believe our proprietary stem cell
technologies may enable therapies to replace specific cells that have been
damaged or destroyed, permitting the restoration of function through the
replacement of normal cells where this has not been possible in the past. In our
research, we have shown that hosts accept CNS stem cells that are transplanted
into them, and that the cells continue to migrate and specialize to produce
mature neurons and glial cells.

    More generally, because the stem cell is the pivotal cell that produces all
the functional mature cell types in an organ, we believe these cells, if
successfully identified and developed for transplantation, may serve as
platforms for five major areas of regenerative medicine and biotechnology:

    - tissue repair and replacement,

    - correction of genetic disorders,

    - drug discovery and screening,

    - gene discovery and use, and

    - diagnostics.

    We will be pursuing alliances in these key areas.

                                       24

OUR PLATFORM OF STEM CELL TECHNOLOGIES

    Stem cells have two defining characteristics:

    - some of the cells developed from stem cells produce all the kinds of
      mature cells making up the particular organ; and

    - they "self renew"--that is, other cells developed from stem cells are
      themselves new stem cells, thus permitting the process to continue again
      and again.

    Stem cells exist for many systems of the human body: the blood and immune
system; the central and peripheral nervous systems (including the brain); and
the liver, pancreas endocrine, and skin systems. These cells are responsible for
organ regeneration during normal cell replacement and, to a limited extent,
after injury. We believe that further research and development will allow stem
cells to be cultivated and administered in ways that enhance their natural
function, so as to form the basis of therapies that will replace specific
subsets of cells that disease, injury or genetic defect has damaged or
destroyed.

    We also believe that the person or entity that first identifies and isolates
a stem cell and defines methods to culture any of the finite number of different
types of human stem cells will be able to obtain patent protection for the
methods and the composition, making the commercial development of stem cell
treatment and possible cure of currently intractable diseases financially
feasible.

    Our strategy is to be the first to identify, isolate and patent multiple
types of human stem and progenitor cells with commercial importance. Our
portfolio of issued patents includes a method of culturing normal human central
nervous system stem and progenitor cells in our proprietary chemically defined
medium. Our published studies show that these cultured and expanded cells give
rise to all three major cell types of the central nervous system. Also, a
separate study that we sponsored that used these cultured stem and progenitor
cells showed that the cells are accepted, migrate, and successfully specialize
to produce neurons and glial cells.

    More recently, we announced the results of a new study that showed that
markers present on the surface of freshly obtained brain cells can successfully
isolate human central nervous system stem cells. We believe this is the first
reproducible process for isolating highly purified populations of
well-characterized normal human central nervous system stem cells, and have
applied for a composition of matter patent. Because the cells are highly
purified and have not been genetically modified, they may be especially suitable
for transplantation and may provide a safer and more effective alternative to
therapies that are based on cells derived from cancer cells, cells modified by a
cancer gene, an unpurified mixture of cell types, or animal-derived cells. We
have also filed an improved process patent for the growth and expansion of these
purified normal human central nervous system cells.

    Neurological disorders such as Parkinson's disease, epilepsy, Alzheimer's
disease, and the side effects of stroke, affect a significant portion of the
U.S. population and there currently are no effective long-term therapies for
them. We believe that therapies based on our process for identifying, isolating
and culturing neural stem and progenitor cells may be useful in treating such
diseases. We are continuing to research and develop human central nervous system
stem and progenitor cell-based therapies for these diseases.

    We continue to research the islet stem cell in the human pancreas and the
liver stem cell. Islet cells are the cells that produce insulin, so islet stem
cells may be useful in the treatment of Type 1 diabetes and those cases of Type
2 diabetes where insulin secretion is defective. Liver stem cells may be useful
in the treatment of diseases such as hepatitis, cirrhosis of the liver and liver
cancer.

                                       25

EXPECTED ADVANTAGES OF OUR STEM CELL TECHNOLOGY

NO OTHER TREATMENT

    To the best of our knowledge, no one has developed an FDA-approved method
for replacing lost or damaged tissues from the human nervous system. Replacement
of tissues in other areas of the human body is limited to those few sites, such
as bone marrow or peripheral blood cell transplants, where transplantation of
the patient's own cells is now feasible. In a few additional areas, including
the liver, transplantation of donor organs is now used, but is limited by the
scarcity of organs available through donation. We believe that our stem cell
technologies have the potential to reestablish function in at least some of the
patients who have suffered loss of nervous system tissue.

REPLACED CELLS PROVIDE NORMAL FUNCTION

    Because stem cells can duplicate themselves, or self-renew, and specialize
into the multiple kinds of cells that are commonly lost in various diseases,
transplanted stem cells may be able to migrate limited distances to the proper
location within the body, to expand and specialize and to replace damaged or
defective cells, facilitating the return to proper function. We believe that
such replacement of damaged or defective cells by functional cells is unlikely
to be achieved with any other treatment.

RESEARCH EFFORTS AND PRODUCT DEVELOPMENT PROGRAMS

OVERVIEW OF RESEARCH AND PRODUCT DEVELOPMENT STRATEGY

    We have devoted substantial resources to research the isolation and
development of a series of stem and progenitor cells that would serve as a basis
for replacing diseased or injured cells. Our efforts to date have been directed
at methods to identify, isolate and culture large varieties of stem and
progenitor cells of the human nervous system, liver and pancreas and to develop
therapies utilizing these stem and progenitor cells.

    The following table lists the potential therapeutic indications for, and
current status of, our primary research and product development programs. The
table is qualified in its entirety by reference to the more detailed
descriptions of such programs appearing elsewhere in this prospectus. We
continually evaluate our research and product development and reallocate
resources in light of experimental results, commercial potential, availability
of third party funding, likelihood of near-term efficacy, collaboration success
or significant technology enhancement, or other relevant factors. Our research
and product development programs are in early stages of development and will
require substantial resources to commercialize.

                                       26

RESEARCH AND PRODUCT DEVELOPMENT PROGRAMS



     PROGRAM DESCRIPTION AND OBJECTIVE                           STAGE/STATUS(1)
-------------------------------------------  -------------------------------------------------------
                                                   
          HUMAN NEURAL STEM CELL                                         PRECLINICAL

Repair or replace damaged central nervous            -   Demonstrated IN VITRO the ability to
system tissue (including spinal cord,                    initiate and expand stem cell-containing
degenerated retinas and tissue affected by               human neural cultures and specialization
certain genetic disorders)                               into three types of central nervous system
                                                         cells
                                                     -   Demonstrated the ability of neurosphere-
                                                         initiating stem cells from human brain
                                                     -   Demonstrated in rodent studies that
                                                         transplanted human brain-derived stem cells
                                                         are accepted and properly specialized into
                                                         the three major cell types of the central
                                                         nervous system

         PANCREAS ISLET STEM CELL                                         RESEARCH

Repair or replace damaged pancreas islet             -   Identified markers on the surface of cells
tissue                                                   to isolate and culture islet stem cells of
                                                         the pancreas
                                                     -   Commenced small animal testing

              LIVER STEM CELL                                             RESEARCH
Repair or replace damaged liver tissue               -   Demonstrated the production of hepatocytes
including tissue resulting from certain                  from purified mouse hematopoietic stem
metabolic genetic diseases                               cells
                                                     -   Identified IN VITRO culture assay for
                                                         growth of human bipotent liver progenitor
                                                         cells that can produce both bile duct and
                                                         hepatocytes
                                                     -   Showed that the IN VITRO culture of human
                                                         bipotent liver cells can also grow human
                                                         hepatitis virus


------------------------

(1) "Research" refers to early stage research and product development activities
    IN VITRO, including the selection and characterization of product candidates
    for preclinical testing. "Preclinical" refers to further testing of a
    defined product candidate IN VITRO and in animals prior to clinical studies.

RESEARCH AND DEVELOPMENT PROGRAMS

    Currently, our portfolio of stem cell technology results from our exclusive
licensing of central nervous system, stem and progenitor cell technology, animal
models for the identification and/or testing of stem and progenitor cells and
our own research and development efforts. We believe that therapies using stem
cells represent a fundamentally new approach to the treatment of diseases caused
by lost or damaged tissue. We assembled an experienced team of scientists and
scientific advisors to consult with and advise our scientists on their
continuing research and development of stem and progenitor cells. This team
includes, among others, Irving L. Weissman, M.D., of Stanford University, Fred
H. Gage, Ph.D., of The Salk Institute and David Anderson, Ph.D., of the
California Institute of Technology.

BRAIN STEM AND PROGENITOR CELL RESEARCH AND DEVELOPMENT PROGRAM

    We began our work with central nervous system stem and progenitor cell
cultures in collaboration with NeuroSpheres, Ltd., in 1992. We believe
NeuroSpheres first invented these cultures. Further, NeuroSpheres granted us
exclusive, worldwide licenses, encompassing all uses, to numerous inventions

                                       27

and associated patents and patent applications. These inventions and associated
patents and patent applications are subsequently noted in the section entitled
"License Agreements and Sponsored Research Agreements--NeuroSpheres, Ltd."

    In 1997, our scientists invented a reproducible method for growing human
central nervous system, stem and progenitor cells in cultures. In preclinical IN
VITRO and early IN VIVO studies, we demonstrated that these cells specialize
into all three of the cell types of the central nervous system, or CNS. Because
of these results, we believe that these cells may form the basis for replacement
of cells lost in certain degenerative diseases. We are continuing research into,
and have initiated the development of, our human CNS stem and progenitor cell
cultures. We have initiated the cultures and demonstrated that these cultures
can be expanded for a number of generations IN VITRO in chemically defined
media. In collaboration with us, Dr. Anders Bjorklund has shown that cells from
these cultures can be successfully transplanted and accepted into the brains of
rodents where they subsequently migrated and specialized into the appropriate
cell types for the site of the brain into which they were placed.

    In 1998, we expanded our preclinical efforts in this area by initiating
programs aimed at the discovery and use of specific monoclonal antibodies to
facilitate identification and isolation of CNS and other stem and progenitor
cells or their specialized progeny. Also in 1998, our researchers devised
methods to advance the IN VITRO culture and passage of human CNS stem cells that
resulted in a 100-fold increase in CNS stem and progenitor cell production after
6 passages. The US Patent and Trademark Office has since allowed a patent on
those methods. We are expanding our preclinical efforts toward the goal of
selecting the proper indications to pursue.

    In December 1998, we announced that the U.S. Patent and Trademark Office had
granted patent No. 5,851,832. This patent covered our methods for the human CNS
cell cultures containing central nervous system stem cells, for compositions of
human CNS cells expanded by these methods, and for use of these cultures in
human transplantation. These human CNS stem and progenitor cells expanded in
culture may be useful for repairing or replacing damaged central nervous system
tissue, including the brain and the spinal cord.

    In October 1999, the U.S. Patent and Trademark Office granted patent number
5,968,829 entitled "Human CNS Neural Stem Cells," covering our composition of
matter patent for human CNS stem cells and also allowed a separate patent
application for our media for culturing human CNS stem cells.

    Also in 1999, we announced the filing of a U.S. patent application covering
our proprietary process for the direct isolation of normal human CNS stem cells
based on the markers found to be present on the surface of freshly obtained
brain cells. Since the filing of this patent application, our researchers have
completed a study designed to identify, isolate and culture human CNS stem cells
using this proprietary process. In November 1999, we announced the study's first
results: Our researchers, by using our proprietary markers on the surface of the
cell, had succeeded in identifying, isolating and purifying human CNS stem cells
from brain tissue, and were able to expand the number of these cells in culture.

    We believe that this is the first study to show a reproducible process for
isolating highly purified populations of well-characterized normal human CNS
stem cells. The unmodified cells are normal human CNS stem cells and, therefore,
may be especially suitable for transplantation. In addition, the cells may
provide a safer and more effective alternative to therapies based on cells
derived from cancer cells or from an unpurified mix of many different cell
types, or from animal derived cells.

    In January 2000, we reported what we regard as an even more important
result: In long term animal studies, our researchers took purified and expanded
stem cells and transplanted them into the normal brains of immunodeficient mouse
hosts, where they took hold and grew into neurons and glial cells.

                                       28

    Throughout the study, the transplanted human CNS stem cells survived for as
long as one year and migrated to specific functional domains of the host brain,
with no sign of tumor formation or adverse effects on the animal recipients;
moreover, the cells were still dividing. These findings show that when CNS stem
cells isolated and cultured with our proprietary processes are transplanted,
they adopt the characteristics of the host brain and act like normal stem cells.
In other words, the study suggests the possibility of a continual replenishment
of normal human brain cells.

    As noted above, human CNS stem and progenitor cells harvested and purified
and expanded using our proprietary processes may be useful for creating
therapies for the treatment of degenerative brain diseases such as Parkinson's,
Huntington's and Alzheimer's disease. These conditions affect more than
5 million people in the United States and there are no effective long-term
therapies currently available. We believe the ability to purify human brain stem
cells directly from fresh tissue is important because:

    - it provides an enriched source of normal stem cells, not contaminated by
      other unwanted or diseased cell types, that can be expanded in culture
      without fear of also expanding some unwanted cell types;

    - it opens the way to a better understanding of the properties of these
      cells and how they might be manipulated to treat specific diseases. For
      example, in certain genetic diseases such as Tay Sachs and Gaucher's, a
      key metabolic enzyme required for normal development and function of the
      brain is absent. Brain-derived stem cell cultures might be genetically
      modified to produce those proteins. The modified brain stem cells could be
      transplanted into patients with these genetic diseases;

    - the efficient acceptance of these non-transformed normal human stem cells
      into host brains means that the cell product can be tested in animal
      models for its ability to correct deficiencies caused by various human
      neurological diseases. In addition, this technology could provide a unique
      animal model for the testing of drugs that act on human brain cells either
      for effectiveness of the drug against the disease or its toxicity to human
      nerve cells.

PANCREAS STEM CELLS DISCOVERY RESEARCH PROGRAMS

    Nora Sarvetnick, Ph.D., of The Scripps Research Institute, in collaboration
with some of our senior researchers, has conducted our discovery program
directed to the identification, isolation and culturing of the pancreas stem and
progenitor cells. It is our intention to bring the research on stem and
progenitor cells of the pancreas in house. We expect that Dr. Sarvetnick will
continue to consult with us.

    According to diabetes and juvenile diabetes foundations, between 800,000 and
1.5 million Americans have Type 1 diabetes, which is often called "juvenile
diabetes" and most commonly diagnosed in childhood; and 30,000 new patients are
diagnosed with the disease every year. It is a costly, serious, lifelong
condition, requiring constant attention and insulin injections every day for
survival.

    About 15 million other people in the United States have Type 2 diabetes
mellitus, which is also a chronic and potentially fatal condition; and more than
700,000 new patients are diagnosed annually.

    In 1998, we obtained an exclusive, worldwide license from The Scripps
Research Institute to novel technology developed by Dr. Sarvetnick which may
facilitate the identification and isolation of pancreas stem and progenitor
cells by using a mouse model that continuously regenerates the pancreas. We
believe that stem cells produce the regeneration, in which case this animal
model may be useful for identifying specific markers on the cell surface unique
to the pancreas stem cells. We believe this may lead to the development of
cell-based treatments for Type 1 diabetes and that portion of Type 2 diabetes
characterized by defective secretion of insulin.

                                       29

    In 1999, advances in the research sponsored by us resulted in our obtaining
additional exclusive, worldwide licenses from The Scripps Research Institute to
novel markers on the cell surface. Dr. Sarvetnick and her research team
identified these novel markers as being unique to the pancreas islet stem cell
for which we have now filed a US patent application. In collaboration with
Dr. Sarvetnick, we continue to advance the discovery program directed at the
identification, isolation and culturing of pancreas stem and progenitor cells
using this technology.

LIVER STEM CELLS DISCOVERY RESEARCH PROGRAMS

    We initiated our discovery work for the liver stem and progenitor cell
through a sponsored research agreement with Markus Grompe, Ph.D., of Oregon
Health Sciences University. Dr. Grompe's work focuses on the discovery and
development of a suitable method for identifying and assessing liver stem and
progenitor cells for use in transplantation. In addition, we obtained a
worldwide exclusive license to a novel mouse model of liver failure for
evaluating cell transplantation developed by Dr. Grompe.

    Approximately 1 in 10 Americans suffers from diseases and disorders of the
liver for which there are currently no effective long-term treatments. In 1998,
our researchers continued to advance methods for establishing enriched cell
populations suitable for transplantation in preclinical animal models. We are
focused on discovering and utilizing our proprietary methods to identify,
isolate and culture liver stem and progenitor cells and to evaluate these cells
in preclinical animal models.

    In 1999, our researchers devised a culture assay that we will use in our
efforts to identify liver stem and progenitor cells. In addition to supporting
the growth of an early human liver bipotent progenitor cell, it is possible to
infect this culture with human hepatitis virus, providing a valuable system for
study of the virus. This technology could also provide a unique IN VITRO model
for the testing of drugs that act on, or are metabolized by, human liver cells.

    An important element of our stem cell discovery program is the further
development of intellectual property positions with respect to stem and
progenitor cells. Further, we obtained rights to certain inventions relating to
stem cells from, and are conducting stem cell related research at, several
academic institutions. We expect to expand our search for new stem and
progenitor cells and to seek to acquire rights to additional inventions relating
to stem and progenitor cells from third parties.

WIND-DOWN OF ENCAPSULATED CELL THERAPY RESEARCH AND DEVELOPMENT PROGRAMS

    Until mid-1999, we engaged in research and development in encapsulated cell
therapy technology, or ECT, including a pain control program funded by
AstraZeneca Group plc. The results from the 85-patient double-blind,
placebo-controlled trial of our encapsulated bovine cell implant for the
treatment of severe, chronic pain in cancer patients did not, however, meet the
criteria AstraZeneca had established for continuing trials for the therapy.
Failing to meet this criteria caused AstraZeneca to terminate the collaboration
in June 1999.

    Consequently, in July 1999, we announced plans for the restructuring of our
research operations to abandon all further ECT research and to concentrate our
resources on the research and development of our proprietary platform of stem
cell technology. We reduced our workforce by approximately 68 full-time
employees who had been focused on ECT programs, wound down our research and
manufacturing operations in Lincoln, Rhode Island, and relocated our remaining
research and development activities, and our corporate headquarters, to the
facilities of our wholly owned subsidiary, StemCells California, Inc., in
California. We subleased a portion of our former corporate headquarters building
and our pilot manufacturing and cell processing facility in Rhode Island are
actively seeking to sublease, assign or sell our interest in the remainder.

                                       30

    In December 1999, we sold our intellectual property assets related to our
ECT to Neurotech S.A., a privately held French company, in exchange for a
payment of $3 million, royalties on future product sales, and a portion of
certain revenues Neurotech may in the future receive from third parties. We
transferred these rights to royalties and other payments to Modex. We retained
certain non-exclusive rights to use the ECT in combination with our proprietary
stem cell technology, and in the field of vaccines for prevention and treatment
of infectious diseases.

SUBSIDIARY

STEMCELLS CALIFORNIA, INC.

    On September 26, 1997, we acquired by merger the California corporation
StemCells, Inc., currently StemCells California, Inc., in exchange for 1,320,691
shares of our common stock and options and warrants for the purchase of 259,296
common shares. Simultaneously with the acquisition, its President, Richard M.
Rose, M.D., became our President, Chief Executive Officer and a director, and
Irving L. Weissman, M.D., a founder of the California corporation, became a
member of our board of directors. We, as the sole stockholder of our subsidiary,
voted on February 23, 2000, to amend its Certificate of Incorporation to change
its name to StemCells California, Inc.

CORPORATE COLLABORATIONS

CORPORATE INVESTMENT

    In July 1996, we, together with certain founding scientists, established
Modex Therapeutics, Ltd., a Swiss biotherapeutics company, to pursue extensions
of our former technology of ECT for certain applications outside the central
nervous system. We, along with the scientists, formed Modex, headquartered in
Lausanne, Switzerland, to integrate technologies developed by us and by several
other institutions to develop products to treat diseases such as diabetes,
obesity and anemia. After our disposition of the encapsulated cell technology in
December 1999, we no longer had common research or development interests with
Modex, but continued to hold approximately 17% of its stock. Modex completed an
initial public offering on June 23, 2000, in the course of which we realized a
gain of approximately $1.4 million from the sale of certain shares. After
Modex's IPO, we owned 126,193 shares, or approximately 9%, of Modex's equity,
subject to a lockup until December 23, 2000. The closing market price of Modex
stock on the Swiss Neue Market exchange on January 2, 2001 was 210.00 Swiss
francs, or approximately $130.39, per share. On January 9, 2001, we sold 22,616
Modex shares for a net price of 182.00 Swiss francs per share, which converts to
$112.76 per share, for total proceeds of approximately $2,550,000. In connection
with this sale, we agreed not to resell any more of our remaining 103,577 Modex
shares until April 12, 2001. On April 30, 2001, we sold our remaining 103,577
Modex shares for a net price of 87.30 Swiss francs per share, which converts to
approximately $50.30, for proceeds from that sale of approximately $5,200,000.

LICENSE AGREEMENTS AND SPONSORED RESEARCH AGREEMENTS

SPONSORED RESEARCH AGREEMENTS

    Under Sponsored Research Agreements with The Scripps Research Institute and
Oregon Health Sciences University, we funded certain research in return for
licenses or options to license the inventions resulting from the research. In
addition, we entered into license agreements with the California Institute of
Technology. All of these agreements relate largely to stem or progenitor cells
and or to processes and methods for the isolation, identification, expansion or
culturing of stem or progenitor cells.

    Our research agreement with Scripps expired on November 14, 2000. It is our
intention to bring the research on stem and progenitor cells of the pancreas in
house. Dr. Nora Sarvetnick, who led the

                                       31

research at Scripps, will continue to consult with us. Our license agreements
with Scripps are not affected by the expiration of the research agreement. They
will terminate upon expiration, revocation or invalidation of the patents
licensed to us, unless governmental regulations require a shorter term. In
addition, these license agreements are subject to early termination if we breach
without curing our obligations under the agreement or if we declare bankruptcy,
and we can terminate the license agreements at any time upon notice. Upon the
initiation of the Phase II trial for our first product using Scripps licensed
technology, we must pay Scripps $50,000 and upon completion of that Phase II
trial we must pay Scripps an additional $125,000. Upon approval of the first
product for sale in the market, we must pay Scripps $250,000. Our license
agreements with the California Institute of Technology will expire upon
expiration, revocation, invalidation or abandonment of the patents licensed to
us. We can terminate any of these license agreements by giving 30 days' notice
to the California Institute of Technology. Either party can terminate these
license agreements upon a material breach by the other party. We issued 12,800
shares of common stock amounting to $10,000 to the California Institute of
Technology upon execution of the license agreements, and we must pay an
additional $10,000 upon the issuance of the patent licensed to us under the
relevant agreement. In addition, we will pay $5,000 on the anniversary of the
issuance of the patent licensed to us under the relevant agreement. These
amounts are creditable against royalties we must pay under the license
agreements. The maximum royalties that we will have to pay to the California
Institute of Technology will be $2 million per year, with an overall maximum of
$15 million. Once we pay the $15 million maximum royalty, the licenses will
become fully paid and irrevocable.

LICENSE AGREEMENTS

    We entered into a number of license agreements with commercial and
non-profit institutions, as well as a number of research-plus-license agreements
with academic organizations. The research agreements provide that we will fund
certain research costs, and in return, will possess a license or an option for a
license to the resulting inventions. Under the license agreements, we will
typically be subject to obligations of due diligence and the requirement to pay
royalties on products that use patented technology licensed under such
agreements.

SIGNAL PHARMACEUTICALS, INC.

    In December 1997, we entered into two license agreements with Signal
Pharmaceuticals, Inc. under which each party licensed to the other certain
patent rights and biological materials for use in defined fields. An initial
disagreement as to the interpretation of the licensed rights was resolved by the
parties, and the agreements are operating in accordance with their terms.
Celgene has now acquired Signal. Each agreement with Signal will terminate at
the expiration of all patents licensed under it, but the licensing party can
terminate earlier if the other party breaches its obligations under the
agreement or declares bankruptcy. Further, the party receiving the license can
terminate the agreement at any time upon notice to the other party. Under these
agreements, we must reimburse Signal for payments it must make to the University
of California based on products we develop and for 50% of certain other payments
Signal must make.

                                       32

NEUROSPHERES, LTD.

    In March 1994, we entered into a Contract Research and License Agreement
with NeuroSpheres, Ltd., which was clarified in a License Agreement dated as of
April 1, 1997. Under the agreement as clarified, we obtained an exclusive patent
license from NeuroSpheres in the field of transplantation, subject to a limited
right of NeuroSpheres to purchase a nonexclusive license from us, which right
was not exercised and has expired. We developed additional intellectual property
relating to the subject matter of the license. We entered into an additional
license agreement with NeuroSpheres as of October 30, 2000, under which we
obtained an exclusive license in the field of non-transplant uses, such as drug
discovery and drug testing, so that together the licenses are exclusive for all
uses of the technology. We made up-front payments to NeuroSpheres of 65,000
shares of our common stock in October 2000 and $50,000 in January 2001, and we
will make additional cash payments when milestones are achieved in the
non-transplant field, or in any products employing NeuroSpheres patents for
generating cells of the blood and immune system from neural stem cells. In
addition we reimbursed Neurospheres for patent costs amounting to $341,000.
Milestone payments would total $500,000 for each product that is approved for
market. Our agreements with NeuroSpheres will terminate at the expiration of all
patents licensed to us, but can terminate earlier if we breach without curing
our obligations under the agreement or if we declare bankruptcy. We would have a
security interest in the licensed technology in the event that NeuroSpheres
declares bankruptcy.

MANUFACTURING

    The keys to successful commercialization of brain stem and progenitor cells
are efficacy, safety, consistency of the product, and economy of the process. We
expect to address these issues through appropriate testing and by banking
representative vials of large-scale cultures. Commercial production is expected
to involve expansion of banked cells and packaging them in appropriate
containers after formulating the cells in an effective carrier. In addition, the
carrier may be used to improve the stability and acceptance of the stem cells or
their progeny. Our stem and progenitor cell programs are still in an early stage
and, therefore, all of the issues surrounding the manufacture of stem and
progenitor cell products are not yet clear.

MARKETING

    We expect to market and sell our products primarily through co-marketing,
licensing or other arrangements with third parties. There are a number of
substantial companies with existing distribution channels and large marketing
resources who are well equipped to market and sell our products. We intend to
have the marketing of our products undertaken by such partners, although we may
seek to retain limited marketing rights in specific narrow markets where the
product may be addressed by a specialty or niche sales force.

PATENTS, PROPRIETARY RIGHTS AND LICENSES

    We believe that proprietary protection of our inventions will be of major
importance to our future business. We possess an aggressive program of
vigorously seeking and protecting our intellectual property which we believe
might be useful in connection with our products. In addition, we believe that
our know-how will provide a significant competitive advantage, and we intend to
continue to develop and protect our proprietary know-how. We may also from time
to time seek to acquire licenses to important externally developed technologies.

    We possess exclusive or non-exclusive rights to a portfolio of patents and
patent applications related to various stem and progenitor cells and methods of
deriving and using them. These patents and patent applications relate mainly to
compositions of matter, methods of obtaining such cells, and methods for
preparing, transplanting and utilizing such cells. Currently, our U.S. patent
portfolio in the

                                       33

neural stem cell therapy area includes 25 issued U.S. patents. An additional
fifteen patent applications are pending, four of which the U.S. Patent and
Trademark Office has allowed.

    We own, or have filed, the following United States Patents and patent
applications:

    - U.S. Patent Number 5,968,829 (Human CNS neural stem cells)

    - U.S. Patent Number 6,103,530 (Human CNS neural stem cells--culture media)

    - U.S. Patent Number 6,238,922 (Use of collagenase in the preparation of
      neural stem cell cultures)

    - U.S. Patent Number 6,242,666 (An animal model for identifying a common
      stem/progenitor to liver cells and pancreatic cells)

    - Application Number WO 99/11758 (Cultures of human CNS neural stem cells)

    - Application Number WO 00/36091 (An animal model for identifying a common
      stem/progenitor to liver cells and pancreatic cells)

    - Application Number WO98/50526 (Generation, characterization, and isolation
      of neuroepithelial stem cells and lineage restricted intermediate
      precursor)

    - Application Number WO 00/50572 (Use of collagenase in the preparation of
      neural stem cell cultures)

    - Application Number WO 00/47762 (Enriched neural stem cell populations and
      methods of identifying, isolating, and enriching neural stem cells)

    We licensed the following United States Patents or pending patent
applications from Neurospheres Holdings Ltd.:

    - U.S. Patent Number 5,851,832 (IN VITRO proliferation)

    - U.S. Patent Number 5,750,376 (IN VITRO genetic modification)

    - U.S. Patent Number 5,981,165 (IN VITRO production of dopaminergic cells
      from mammalian central nervous system multipotent stem cell compositions)

    - U.S. Patent Number 6,093,531 (Generation of hematopoietic cells from
      multipotent neural stem cells)

    - U.S. Patent Number 5,980,885 (Methods for inducing IN VIVO proliferation
      of precursor cells)

    - U.S. Patent Number 6,071,889 (Methods for IN VIVO transfer of a nucleic
      acid sequence to proliferating neural cells)

    - U.S. Patent Number 6,165,783 (Methods of inducing differentiation of
      multipotent neural stem cells)

    - Application Number WO 93/01275 (Mammalian central nervous system
      multipotent stem cell compositions)

    - Application Number WO 94/09119 (Remyelination using mammalian central
      nervous system multipotent stem cell compositions)

    - Application Number WO 94/10292 (Biological factors useful in
      differentiating mammalian central nervous system multipotent stem cell
      compositions)

    - Application Number WO 94/16718 (Genetically engineered mammalian central
      nervous system multipotent stem cell compositions)

                                       34

    - Application Number WO 96/15224 (Differentiation of mammalian central
      nervous system multipotent stem cell compositions)

    - Application Number WO 99/2196 (Erythropoietin-mediated neurogenesis)

    - Application Number WO 99/16863 (Generation of hematopoietic cells)

    - Application Number WO 98/22127 (Pretreatment with growth factors to
      protect against CNS damage)

    - Application Number WO 97/3560 (IN SITU manipulation of cells of the
      hippocampus)

    - Application Number WO 96/09543 (IN VITRO models of CNS functions and
      dysfunctions)

    - Application Number WO 95/13364 (IN SITU modification and manipulation of
      stem cells of the CNS)

    - Application Number WO 96/15226 (IN VITRO production of dopaminergic cells
      from mammalian central nervous system multipotent stem cell composition)

    - Application Number WO 96/15266 (Regulation of neural stem cell
      proliferation).

    We licensed the following United States Patents or pending patent
applications from the University of California, San Diego:

    - U.S. Patent Number 5,776,948 (Method of production of neuroblasts)

    - U.S. Patent Number 6,013,521 (Method of production of neuroblasts)

    - U.S. Patent Number 6,020,197 (Method of production of neuroblasts)

    - Application Number WO 94/16059 (Method of production of neuroblasts)

    - Application Number WO 00/52143 (Methods of enriching a population of
      uncultured cells).

    We licensed the following United States Patents or pending patent
applications from the California Institute of Technology:

    - U.S. Patent Number 5,629,159 (Immortalization and disimmortalization of
      cells)

    - Application Number WO 96/40877 (Immortalization and disimmortalization of
      cells)

    - U.S. Patent Number 5,935,811 (Neuron restrictive silencer factor proteins)

    - Application Number WO 96/27665 (Neuron restrictive silencer factor
      proteins)

    - U.S. Patent Number 5,589,376 (Mammalian neural crest stem cells)

    - U.S. Patent Number 5,824,489 (Methods for isolating mammalian multipotent
      neural crest stem cells)

    - Application Number WO 94/02593 (Mammalian neural crest stem cells)

    - U.S. Patent Number 5,654,183 (Genetically engineered mammalian neural
      crest stem cells)

    - U.S. Patent Number 5,928,947 (Mammalian multipotent neural crest stem
      cells)

    - U.S. Patent Number 5,693,482 (IN VITRO neural crest stem cell assay)

    - U.S. Patent Number 6,001,654 (Methods for differentiating neural stem
      cells to neurons or smooth muscle cells (TGFb))

    - Application Number WO 98/48001 (Methods for differentiating neural stem
      cells to neurons or smooth muscle cells (TGFb))

                                       35

    - U.S. Patent Number 5,672,499 (Methods for immortalizing multipotent neural
      crest stem cells)

    - U.S. Patent Number 5,849,553 (Immortalizing and disimmortalizing
      multipotent neural crest stem cells)

    - U.S. Patent Number 6,033,906 (Differentiating mammalian neural stem cells
      to glial cells using neuregulins).

    We also rely upon trade secret protection for our confidential and
proprietary information and take active measures to control access to that
information. For instance, our policy is to require our employees, consultants
and significant scientific collaborators and sponsored researchers to execute
confidentiality agreements upon the commencement of an employment or consulting
relationship with us. These agreements generally provide that all confidential
information developed or made known to the individual by us during the course of
the individual's relationship with us is to be kept confidential and not
disclosed to third parties except in specific circumstances. In the case of
employees and consultants, the agreements generally provide that all inventions
conceived by the individual in the course of rendering services to us shall be
our exclusive property.

    We have obtained rights from universities and research institutions to
technologies, processes and compounds that it believes may be important to the
development of its products. These agreements typically require us to pay
license fees, meet certain diligence obligations and, upon commercial
introduction of certain products, pay royalties. These include exclusive license
agreements with NeuroSpheres, The Scripps Institute, the California Institute of
Technology and the Oregon Health Sciences University to certain patents and
know-how regarding present and certain future developments in neural and
pancreatic stem cells.

COMPETITION

    The targeted disease states for our initial products in some instances
currently have no effective long-term therapies. We do, however, expect that our
initial products will have to compete with a variety of therapeutic products and
procedures. Major pharmaceutical companies currently offer a number of
pharmaceutical products to treat neurodegenerative and liver diseases, diabetes
and other diseases for which our technologies may be applicable. Many
pharmaceutical and biotechnology companies are investigating new drugs and
therapeutic approaches for the same purposes, which may achieve new efficacy
profiles, extend the therapeutic window for such products, alter the prognosis
of these diseases, or prevent their onset. We believe that our products, when
successfully developed, will compete with these products principally on the
basis of improved and extended efficacy and safety and their overall economic
benefit to the health care system. The market for therapeutic products that
address degenerative diseases is large, and competition is intense. We expect
competition to increase. We believe that our most significant competitors will
be fully integrated pharmaceutical companies and more established biotechnology
companies. Smaller companies may also be significant competitors, particularly
through collaborative arrangements with large pharmaceutical or biotechnology
companies. Many of these competitors possess significant products approved or in
development that could be competitive with our potential products.

    Competition for our stem and progenitor cell products may be in the form of
existing and new drugs, other forms of cell transplantation, ablative and
simulative procedures, and gene therapy. We believe that some of our competitors
are also trying to develop stem and progenitor cell-based technologies. We
expect that all of these products will compete with our potential stem and
progenitor cell products based on efficacy, safety, cost and intellectual
property positions.

    In addition, we may face competition from companies that filed patent
applications relating to the use of genetically modified cells to treat disease,
disorder or injury. We may be required to seek licenses from these competitors
in order to commercialize certain of our proposed products.

                                       36

    Once our products are developed and receive regulatory approval, they must
then compete for market acceptance and market share. For certain of our
potential products, an important success factor will be the timing of market
introduction of competitive products. This is a function of the relative speed
with which we and our competitors can develop products, complete the clinical
testing and approval processes, and supply commercial quantities of a product to
market. These competitive products may also impact the timing of clinical
testing and approval processes by limiting the number of clinical investigators
and patients available to test our potential products.

    While we believe that the primary competitive factors will be product
efficacy, safety, and the timing and scope of regulatory approvals, other
factors include, in certain instances, obtaining marketing exclusivity under the
Orphan Drug Act, availability of supply, marketing and sales capability,
reimbursement coverage, price, and patent and technology position.

GOVERNMENT REGULATION

    Our research and development activities are subject to regulation by
numerous governmental authorities in the United States and other countries. The
future manufacturing and marketing of our potential products will be likewise
regulated.

    In the United States, pharmaceuticals, biologicals and medical devices are
subject to rigorous Food and Drug Administration, or FDA, regulation. The
Federal Food, Drug and Cosmetic Act and the Public Health Service Act, as well
as other Federal and state statutes and regulations, govern the testing,
manufacture, safety, efficacy, labeling, storage, export, record keeping,
approval, marketing, advertising and promotion of our potential products.
Product development and approval within this regulatory framework takes a number
of years and involves significant uncertainty combined with the expenditure of
substantial resources. In addition, the federal, state, and other jurisdictions
have restrictions on the use of fetal tissue.

FDA APPROVAL

    The steps required before our potential products may be marketed in the
United States include:



                  STEPS                                      CONSIDERATIONS
-----------------------------------------  --------------------------------------------------
                                              
1. Preclinical laboratory and animal       Preclinical tests include laboratory evaluation of
tests                                      the product and animal studies in specific disease
                                           models to assess the potential safety and efficacy
                                           of the product and our formulation as well as the
                                           quality and consistency of the manufacturing
                                           process.

2. Submission to the FDA of an             The results of the preclinical tests are submitted
application for an Investigational New     to the FDA as part of an IND, and the IND becomes
Drug Exemption, or IND, which must become  effective 30 days following its receipt by the
effective before human clinical trials in  FDA, as long as there are no questions, requests
the U.S. may commence                      for delay or objections from the FDA.


                                       37




                  STEPS                                      CONSIDERATIONS
-----------------------------------------  --------------------------------------------------
                                              
                                           Clinical trials involve the evaluation of the
                                           product in healthy volunteers or, in a small
3. Adequate and well-controlled human      number of patients under the supervision of a
clinical trials to establish the safety    qualified physician. Clinical trials are conducted
and efficacy of the product                in accordance with protocols that detail the
                                           objectives of the study, steps to monitor safety
                                           and the efficacy criteria to be evaluated. Any
                                           product administered in a U.S. clinical trial must
                                           be manufactured in accordance with clinical Good
                                           Manufacturing Practices, or cGMP, which the FDA
                                           determines. Each protocol is submitted to the FDA
                                           as part of the IND. An independent Institutional
                                           Review Board, or IRB, at the institution at which
                                           the study is conducted must approve the protocol
                                           for each clinical study and obtain the informed
                                           consent of all participants. The IRB will
                                           consider, among other things, the existing
                                           information on the product, ethical factors, the
                                           safety of human subjects, the potential benefits
                                           of the therapy and the possible liability of the
                                           institution.

                                           Clinical development is traditionally conducted in
                                           three sequential phases, which may overlap:

                                                 -  In Phase I, products are typically
                                                    introduced into subjects to test for
                                                    adverse reactions, dosage tolerance,
                                                    absorption and distribution, metabolism,
                                                    excretion and clinical pharmacology.

                                                 -  Phase II studies a limited patient
                                                    population to (i) determine the efficacy
                                                    of the product for specific targeted
                                                    indications and populations, (ii)
                                                    determine optimal dosage and dosage
                                                    tolerance and (iii) identify possible
                                                    adverse effects and safety risks. When a
                                                    dose is chosen and a candidate product
                                                    proves to be effective and safe in Phase
                                                    II evaluations, Phase III trials begin.

                                                 -  Phase III trials are undertaken to
                                                    conclusively demonstrate clinical
                                                    efficacy and test further for safety
                                                    within an expanded patient population,
                                                    generally at multiple study sites.

                                           The FDA continually reviews the clinical trial
                                           plans and results and may suggest changes or
                                           require discontinuance at any time if significant
                                           safety issues arise.

4. Submission to the FDA of marketing      The results of the preclinical and clinical
authorization applications                 studies are submitted to the FDA.


                                       38




                  STEPS                                      CONSIDERATIONS
-----------------------------------------  --------------------------------------------------
                                              
5. FDA approval of the application(s)      The testing and approval process will require
prior to any commercial sale or shipment   substantial time, effort and expense. A number of
of the drug. Biologic product              factors, including relative risks and benefits
manufacturing establishments located in    demonstrated in clinical trials, the availability
certain states also may be subject to      of alternative treatments and the severity of the
separate regulatory and licensing          disease affect the timing. The FDA might request
requirement                                additional animal studies which would also add to
                                           the time.


    After the FDA approves the initial indications and the manufacturing
facility, it might require further clinical trials to grant approval to use the
product for additional indications. The FDA may also require unusual or
restrictive post-marketing testing and surveillance to monitor for adverse
effects, which could involve significant expense. It may also elect to grant
only conditional approvals.

FDA MANUFACTURING REQUIREMENTS

    Among the conditions for product licensure is the requirement that the
prospective manufacturer's quality control and manufacturing procedures conform
to the FDA's cGMP requirement. Even after product licensure approval, the
manufacturer must comply with cGMP on a continuing basis. However, what
constitutes cGMP may change as the state of the art of manufacturing changes.
Domestic manufacturing facilities are subject to regular FDA inspections for
cGMP compliance. The FDA normally holds inspections at least every two years.
The FDA, as well as foreign regulatory authorities with reciprocal inspection
agreements, may periodically inspect foreign manufacturing facilities. Foreign
authorities may also inspect domestic manufacturing facilities.

ORPHAN DRUG ACT

    The Orphan Drug Act provides incentives to drug manufacturers to develop and
manufacture drugs for the treatment of diseases or conditions that affect fewer
than 200,000 individuals in the United States. Drug manufacturers can also seek
orphan drug status for treatments for diseases or conditions that affect more
than 200,000 individuals in the United States if the manufacturer does not
realistically anticipate its product becoming profitable from sales in the
United States. We may apply for orphan drug status for certain of our therapies.
Under the Orphan Drug Act, a manufacturer of a designated orphan product can
seek tax benefits, and the holder of the first FDA approval of a designated
orphan product will receive a seven-year period of marketing exclusivity in the
United States for that product. While the marketing exclusivity of an orphan
drug would prevent other sponsors from obtaining approval of the same compound
for the same indication, it would not prevent other types of products from being
approved for the same use.

PROPOSED FDA REGULATIONS

    Proposed regulations of the FDA and other governmental agencies would place
restrictions on researchers who have a financial interest in the outcome of
their research. Under the proposed regulations, the FDA could apply heightened
scrutiny to studies conducted by such researchers when reviewing applications to
the FDA. Certain of our collaborators have stock options or other equity
interests in us that could subject such collaborators and us to the proposed
regulations.

    Our research and development is based on the use of human stem and
progenitor cells. The FDA has published a "Proposed Approach to Regulation of
Cellular and Tissue-Based Products" which relates to the use of human cells. We
cannot now determine the effects of that approach or what regulatory actions it
might take. Restrictions exist on the testing or use of cells, whether human or
non-human.

                                       39

OTHER REGULATIONS

    In addition, we are also subject to regulations under the Occupational
Safety and Health Act, the Environmental Protection Act, the Toxic Substances
Control Act and other foreign, Federal, state and local regulations.

    Outside the United States, we will be subject to regulations that govern the
import of drugs, as well as foreign regulatory requirements governing human
clinical trials and marketing approval. The requirements vary widely from
country to country. In particular, the European Union, or EU, is revising its
regulatory approach to high tech products, and representatives from the United
States, Japan and the EU are in the process of harmonizing the regulations for
the registration of pharmaceutical products in these three markets.

REIMBURSEMENT AND HEALTH CARE COST CONTROL

    Reimbursement for the costs of treatments and products such as ours from
government health administration authorities, private health insurers and others
is a key element in the success of new health care products. Significant
uncertainty often exists as to the reimbursement status of newly approved health
care products.

    The continuing efforts of governmental and third party payers to contain or
reduce the cost of health care have affected the revenues and profitability of
some health-care related companies. Payers are increasingly attempting to limit
both coverage and the level of reimbursement for new therapeutic products that
the FDA approves. In some cases, they are refusing to provide any coverage for
disease indications for which the FDA has not granted marketing approval. For
example, in certain foreign markets, pricing or profitability of prescription
pharmaceuticals is subject to government control. In the United States, there
have been a number of Federal and state proposals to implement government
control over health care costs.

EMPLOYEES

    As of May 23, 2001, we had 28 full-time employees, eight of whom have Ph.D.
degrees. The equivalent of 21 full-time employees work in research and
development and laboratory support services. A number of our employees have held
positions with other biotechnology or pharmaceutical companies or have worked in
university research programs. No employees are covered by collective bargaining
agreements. We believe our relationships with our employees are good.

SCIENTIFIC ADVISORY BOARD

    Members of our Scientific Advisory Board provide us with strategic guidance
in regard to our research and product development programs, as well as
assistance in recruiting employees and collaborators. Each Scientific Advisory
Board member has entered into a consulting agreement with us. These consulting
agreements specify the compensation to be paid to the consultant and require
that all information about our products and technology be kept confidential. All
of the Scientific Advisory Board members are employed by employers other than us
and may have commitments to other entities that limit their availability to us.
The Scientific Advisory Board members have generally agreed, however, for so
long as they serve as consultants to us, not to provide any services to any
other entities that would conflict with the services the member provides to us.
Members of the Scientific Advisory Board offer consultation on specific issues
encountered by us as well as general advice on the directions of appropriate
scientific inquiry for us. In addition, Scientific Advisory Board members assist
us in assessing the appropriateness of moving our projects to more advanced
stages. The following persons are members of our Scientific Advisory Board:

    - Irving L. Weissman, M.D., is the Karel and Avice Beekhuis Professor of
      Cancer Biology, Professor of Pathology and Professor of Developmental
      Biology at Stanford University.

                                       40

      Dr. Weissman was a cofounder of SyStemix, Inc., and Chairman of its
      Scientific Advisory Board. He has served on the Scientific Advisory Boards
      of Amgen Inc., DNAX and T-Cell Sciences, Inc. Dr. Weissman is Chairman of
      the Scientific Advisory Board of StemCells.

    - David J. Anderson, Ph.D., is Professor of Biology, California Institute of
      Technology, Pasadena, California and Investigator, Howard Hughes Medical
      Institute.

    - Fred H. Gage, Ph.D., is Professor, Laboratory of Genetics, The Salk
      Institute for Biological Studies, La Jolla, California and Adjunct
      Professor, Department of Neurosciences, University of California, San
      Diego, California.

                                       41

                                   MANAGEMENT

DIRECTORS, EXECUTIVE OFFICERS AND KEY EMPLOYEES

    The following table sets forth the name, age as of December 31, 2000, and
position of each of our executive officers, key members of management, and
directors.



NAME                                          AGE                       POSITION
----                                        --------   ------------------------------------------
                                                 
John J. Schwartz, Ph.D....................     67      Director, Chairman of the Board
Martin M. McGlynn.........................     54      Director, President and Chief Executive
                                                       Officer
Mark J. Levin.............................     50      Director
Roger M. Perlmutter M.D., Ph.D............     48      Director
Irving L. Weissman, M.D...................     61      Director
Ann Tsukamoto, Ph.D.......................     48      Vice President, Scientific Operations


------------------------

- JOHN J. SCHWARTZ, PH.D., was elected to the board of directors in
  December 1998 and was elected Chairman of the board at the same time. He was
  formerly Senior Vice President and General Counsel of SyStemix, Inc. from 1993
  to 1995, and then President and Chief Executive Officer of SyStemix, Inc. from
  1995 to 1997. Dr. Schwartz is currently President of Quantum Strategies
  Management Company, a registered investment advisor located in Atherton,
  California. Prior to his positions at SyStemix, he served as Assistant
  Professor and a Vice President and General Counsel at Stanford University in
  California. Dr. Schwartz graduated from Harvard Law School in 1958 and
  received his Ph.D. in physics from the University of Rochester in 1966.

- MARTIN M. MCGLYNN joined us on January 15, 2001 when he was appointed
  President and Chief Executive Officer of us and our wholly-owned subsidiary,
  StemCells California, Inc. From 1994 until he joined us, Mr. McGlynn was
  President and Chief Executive Officer of Pharmadigm, Inc., a privately held
  company in Salt Lake City, Utah, engaged in research and development in the
  fields of inflammation and genetic immunization. Mr. McGlynn received a
  bachelor of commerce degree from University College, Dublin, Ireland in 1968,
  a diploma in industrial engineering from the Irish Institute of Industrial
  Engineering in 1970, and a diploma in production planning from the University
  of Birmingham, England in 1971.

- MARK J. LEVIN is a founder and has served as a director since our inception in
  1988. From inception until January 1990 and from May 1990 until
  February 1991, Mr. Levin served as our President and acting Chief Executive
  Officer. From November 1991 until March 1992, he served as Chief Executive
  Officer of Tularik, Inc., a biotechnology company. From August 1991 until
  August 1993, Mr. Levin was Chief Executive Officer and a director of
  Focal, Inc., a biomedical company. Mr. Levin is currently the Chairman and
  Chief Executive Officer of Millennium Pharmaceuticals, Inc., a biotechnology
  company. Mr. Levin is also currently on the boards of directors of Focal, Inc.
  and Tularik, Inc.

- ROGER M. PERLMUTTER, M.D., PH.D., was elected to the board of directors in
  December 2000. Dr. Perlmutter is Executive Vice President, Research and
  Development, of Amgen, Inc., a position he has held since January 2001. Prior
  to joining Amgen, Dr. Perlmutter was Executive Vice President, Worldwide Basic
  Research and Preclinical Development, Merck Research Laboratories, a division
  of Merck & Co., Inc., a position he held since August 1999. He joined Merck in
  February 1997 as Senior Vice President, Merck Research Laboratories, from
  February 1997 to December 1998 and as Executive Vice President from
  February 1999 to July 1999. Prior to joining Merck, Dr. Perlmutter was a
  professor in the Departments of Immunology, Biochemistry and Medicine at the
  University of Washington from January 1991 to January 1997 and served as
  chairman of the Department of Immunology at the University of Washington from
  May 1989 to January 1997. He also was an Investigator at the Howard Hughes
  Medical Institute from July 1984 to

                                       42

  February 1997. Dr Perlmutter has been a member of the board of directors of
  The Irvington Institute for Immunological Research since 1997 and of the
  Institute for Systems Biology since 1999.

- IRVING L. WEISSMAN, M.D., has served as a director since September 1997. He
  has been a consultant to us since September 1997 and is the Chairman of our
  Scientific Advisory Board. He is the Karel and Avice Beekhuis Professor of
  Cancer Biology, Professor of Pathology and Professor of Developmental Biology
  at Stanford University. Dr. Weissman is a cofounder of SyStemix, Inc., and a
  former Chairman of its Scientific Advisory Board. He has served on the
  Scientific Advisory Boards of Amgen Inc., DNAX and T-Cell Sciences, Inc.
  Dr. Weissman is a member of the National Academy of Sciences.

- ANN TSUKAMOTO, PH.D., joined us in November 1997 as Senior Director,
  Scientific Operations, and was appointed Vice President, Scientific Operations
  in June 1998. From 1989 until she joined us, Dr. Tsukamoto was employed at
  SyStemix, Inc., where she served in various research capacities before
  transitioning to the position of Director of Clinical Science. At
  SyStemix, Inc., Dr. Tsukamoto assisted in the launch of its clinical research
  program for the hematopoietic stem cell. She received her Ph.D. degree from
  the University of California, Los Angeles and did postdoctoral research with
  Dr. Harold Varmus at the University of California, San Francisco.
  Dr. Tsukamoto is an inventor on six issued U.S. Patents related to the human
  hematopoietic stem cell. As of March 5, 2001, Dr. Tsukamoto became a member of
  the Board of Directors for the Society of Regenerative Medicine and Stem Cell
  Biology.

BOARD COMPOSITION

    Our certificate of incorporation and by-laws provide for the classification
of the board of directors into three classes, as nearly equal in number as
possible, with the term of office of one class expiring each year. Dr. Weissman
is in the class of directors whose term expires at our annual meeting in 2002.
Mr. McGlynn and Dr. Perlmutter are in the class of directors whose term expires
in 2003. Mr. Levin and Dr. Schwartz are in the class of directors whose term
expires in 2004. There are no family relationships between any of our directors
or executive officers. Our executive officers are elected by, and serve at the
discretion of, the board of directors.

DIRECTOR COMPENSATION

    We currently pay no additional remuneration to Mr. McGlynn, our president
and chief executive officer, for his service as a director.

    One of our non-employee directors, Dr. Weissman, also serves us as a
compensated consultant. See "Related Party Transactions--Compensation Paid to
Dr. Weissman."

    We have adopted the following methodology for compensating our directors:
upon election or appointment to an initial term on the board, we will grant a
director an option to purchase 20,000 shares at fair market value, which option
will vest ratably over 3 years. On the third anniversary date, each re-elected
director will be granted an additional option to purchase 15,000 shares at fair
market value, which option will vest ratably over 3 years. In addition, each
director will receive a retainer of $18,000 annually and the Chairman of the
board of directors will receive a retainer of $35,000 annually, each payable in
options to purchase our common stock at $.25 per share.

COMMITTEES OF THE BOARD OF DIRECTORS

    Our board of directors has an audit committee, a compensation and stock
option committee and a single-member stock option committee. The board may also
establish other committees to assist in the discharge of its responsibilities.

                                       43

    The audit committee oversees our financial reporting process on behalf of
the board of directors, makes recommendations to the board regarding the
independent auditors to be nominated for election by the stockholders, reviews
the independence of such auditors, approves the scope of their annual audit
activities, reviews their audit results, assures that our financial reporting is
of high quality, and reviews the interim financial statements with our
management and the independent auditors prior to the filing of our Quarterly
Report on Form 10-Q. Dr. Schwartz, Dr. Perlmutter and Mr. Levin make up the
audit committee.

    The duties of the compensation and stock option committee are to make
recommendations to the board and our management concerning salaries in general,
determine executive compensation, and approve incentive compensation. The
compensation and stock option committee currently comprises Mr. Levin and
Dr. Schwartz. The single-member stock option committee has limited authority to
make stock option grants to our employees, other than officers and directors,
under our 2001 Equity Incentive Plan. Mr. McGlynn is the sole member of this
committee.

COMPENSATION COMMITTEE INTERLOCKS AND INSIDER PARTICIPATION

    The following non-employee directors served on the compensation and stock
option committee in 2000: Mr. Levin and Dr. Schwartz. In 1989, 1990 and 1991,
Mr. Levin was one of our executive officers.

    We entered into a consulting services agreement with Dr. Schwartz on
July 27, 1998, as amended December 19, 1998, for strategic business advice and
counseling services, including assistance in the negotiation and consummation of
strategic collaboration transactions specified by us. Dr. Schwartz was elected
to the Board of Directors on December 19, 1998 and became a member of the
compensation and stock option committee on that date. During the fiscal year
ended December 31, 1999, we made payments to Dr. Schwartz under the consulting
services agreement and the letter agreement dated December 19, 1998 and amended
as of July 1, 1999, under which he served as a Director and Chairman of the
Board. See "Related Party Transactions." Both the consulting services agreement
and the letter agreement were terminated as of March 31, 2001.

    We believe the terms of these agreements were no less favorable to us than
could have been obtained from unaffiliated third parties.

                                       44

EXECUTIVE COMPENSATION

    The following table sets forth the compensation paid by us to our Chief
Executive Officers during the fiscal years ended December 31, 2000, 1999 and
1998 and the two other most highly compensated executive officers who served in
such capacities during the fiscal year ended December 31, 2000. There were no
other persons serving as executive officers at the end of such fiscal year.

                           SUMMARY COMPENSATION TABLE



                                                                                         LONG TERM COMPENSATION
                                                                                        -------------------------
                                                                 ANNUAL COMPENSATION    SECURITIES
                                                                ---------------------   UNDERLYING    ALL OTHER
           NAME AND PRINCIPAL POSITION                 YEAR     SALARY($)   BONUS($)    OPTIONS(#)   COMPENSATION
--------------------------------------------------   --------   ---------   ---------   ----------   ------------
                                                                                      
GEORGE W. DUNBAR, JR. ............................     2000      186,538     50,000      36,031           --
  Acting President and Chief Executive Officer(1)      1999                              48,000

RICHARD M. ROSE M.D. .............................     2000      309,632         --          --           --
  Chief Executive Officer(2)                           1999      279,974         --          --        4,667(3)
                                                       1998      286,553         --     150,000(4)    11,330(5)

ANN TSUKAMOTO, PH.D. .............................     2000      159,054         --          --        4,783(6)
  VP, Scientific Operations

RONNDA BARTEL, PH.D. .............................     2000      129,668         --          --        3,245(8)
  VP, Scientific Development(7)


--------------------------

(1) Mr. Dunbar became Acting President and Chief Executive Officer effective as
    of February 1, 2000, and resigned from that position effective as of
    January 15, 2001.

(2) Dr. Rose became Chief Executive Officer on September 26, 1997. Dr. Rose
    resigned as a director and officer of the company and its wholly owned
    subsidiary effective as of January 31, 2000.

(3) Represents the personal portion of the use of a company vehicle, as well as
    $5,000 of fair market value of our matching contributions of common stock to
    Dr. Rose's account in the company's 401(k) Plan.

(4) Represents the regrant of an option in the original amount of 200,000 shares
    which was reduced to 150,000 shares as a result of the employee equity
    incentive repricing plan approved by the Board of Directors on
    July 10,1998.

(5) Represents $4,666.56 of fair market value of the company matching
    contributions of common stock to Dr. Rose's account in our 401(k) Plan.

(6) Represents $4,783 of fair market value of the company matching contributions
    of common stock to Dr. Tsukamoto.

(7) Dr. Bartel resigned as of July 13, 2001.

(8) Represents $3,245 of fair market value of the company matching contributions
    of common stock to Dr. Bartel.

OPTION GRANTS IN LAST YEAR

    The following table provides information on option grants in 2000 to
Mr. Dunbar, the only named executive officer to be granted options in 2000.

                                       45

                           OPTION GRANTS IN LAST YEAR



                                                                                           POTENTIAL REALIZABLE VALUE
                              SECURITIES      PERCENT OF                                   AT ASSUMED ANNUAL RATES OF
                              UNDERLYING     TOTAL OPTIONS                                STOCK PRICE APPRECIATION FOR
                                OPTIONS       GRANTED TO       EXERCISE                           OPTION TERM
                                GRANTED      EMPLOYEES IN       PRICE       EXPIRATION   ------------------------------
NAME                         (# OF SHARES)      2000(1)      ($/SHARE)(2)      DATE       0%($)      5%($)      10%($)
----                         -------------   -------------   ------------   ----------   --------   --------   --------
                                                                                          
George W. Dunbar, Jr.......      73,000(3)        22%           1.094        10/15/01    271,998    307,120     345,580
                                 12,031(3)         4%           4.156        10/15/01     13,162     19,467      26,371


------------------------

(1) We granted options covering 330,031 shares of common stock to employees in
    the fiscal year ended December 31, 2000.

(2) The exercise price may be paid by delivery of already-owned shares and tax
    withholding obligations related to exercise may be paid by offset of the
    underlying shares, subject to certain conditions.

(3) As of December 31, 2000, options for 85,031 shares were fully vested.

OPTION EXERCISES IN LAST YEAR AND YEAR-END OPTION VALUES

    The following table provides information about option exercises in 2000 by
the named executive officers and the value of such officers' unexercised options
on December 31, 2000.

         AGGREGATED OPTION EXERCISES IN 2000 AND YEAR-END OPTION VALUES



                                                           NUMBER OF SECURITIES
                                                          UNDERLYING UNEXERCISED         VALUE OF UNEXERCISED
                                                                OPTIONS AT              IN-THE-MONEY OPTIONS AT
                              SHARES                          FISCAL YEAR-END            FISCAL YEAR-END($)(1)
                            ACQUIRED ON      VALUE      ---------------------------   ---------------------------
NAME                        EXERCISE(#)   REALIZED($)   EXERCISABLE   UNEXERCISABLE   EXERCISABLE   UNEXERCISABLE
----                        -----------   -----------   -----------   -------------   -----------   -------------
                                                                                  
Richard M. Rose, M.D......    156,250       865,328            --         93,750             --             --
George W. Dunbar, Jr......     42,000       209,160        24,031             --         11,248             --
Ann Tsukamoto, Ph.D.......         --            --        78,082         33,168         29,638         35,161
Ronnda Bartel, Ph.D.......         --            --        19,270         33,230         24,814         43,058


------------------------

(1) Value is based on the difference between the aggregate option exercise price
    and the fair market value as of December 31, 2000. The fair market value of
    the common stock is based on the closing price of the our common stock on
    December 29, 2000 (the last trading day of 2000) on the Nasdaq National
    Market, which was $2.50.

EMPLOYMENT CONTRACTS, TERMINATION OF EMPLOYMENT AND CHANGE OF CONTROL
  ARRANGEMENTS

    Martin McGlynn joined the company as President and Chief Executive Officer
on January 15, 2001. Under the terms of an agreement between Mr. McGlynn and us,
Mr. McGlynn is entitled to an annual base salary of $275,000 per year,
reviewable annually by the board of directors, and a bonus, in the board's sole
discretion, of up to 25% of his base salary. Mr. McGlynn was granted an option
to purchase 400,000 shares of common stock with an exercise price equal to the
fair market value of the common stock on the date of his employment. One-fourth
of these options will vest on the first anniversary of his employment and the
remaining three-fourths will vest in equal monthly installments during his
second through fourth years of employment. The board may, in its sole
discretion, grant Mr. McGlynn a bonus option to purchase up to an additional
25,000 shares. The vesting under the option is subject to acceleration in the
event of certain changes of control. We also agreed to pay Mr. McGlynn a $50,000
relocation bonus and reimburse him for relocation expenses. Our agreement with
Mr. McGlynn provides that if his employment is terminated by us without cause or
by

                                       46

Mr. McGlynn for good reason, he will be entitled to severance payments equal to
one year's base salary and he will receive healthcare benefits under our plans
for one year after termination. If Mr. McGlynn's employment is terminated as a
result of his disability, he will receive up to six months' base salary. If we
terminate Mr. McGlynn's employment for cause or if he resigns without good
reason, he will not be entitled to any severance or other benefits.

STOCK PLANS AND RELATED TRANSACTIONS

    In April 2001, our board of directors adopted the 2001 Equity Incentive
Plan, subject to stockholder approval, which was obtained at our annual meeting
on May 31, 2001.

    The purpose of the Plan is to advance our interests by enhancing our ability
to attract and retain executive officers, employees, directors and other persons
or entities providing services to us who are in a position to make significant
contributions to our success, and to reward participants for such contributions,
through ownership of shares of our common stock. The Plan is intended to
accomplish these goals by enabling us to grant awards in the form of options,
stock appreciation rights, restricted stock, unrestricted stock or deferred
stock, or performance awards, loans or supplemental grants or combinations
thereof, all as more fully described below. The Plan is the successor to both
our 1992 Equity Incentive Plan and our 1992 Stock Option Plan for Non-Employee
Directors. No awards may be made under either of the 1992 plans after
February 12, 2002.

    The Plan is administered by our board of directors. Under the Plan, the
board may grant stock options, stock appreciation rights, restricted stock,
unrestricted stock, deferred stock, and performance awards (in cash or stock),
or combinations thereof, and may waive the terms and conditions of any award. A
total of 3,000,000 shares of common stock may be issued under the Plan.
Employees, including executive officers, directors and other persons or entities
providing services to us or its subsidiaries who are in a position to make a
significant contribution to our success are eligible to receive awards under the
Plan.

    The exercise price of an incentive stock option ("ISO") granted under the
Plan or an option intended to qualify as performance-based compensation under
Section 162(m) of the Code shall not be less than 100% of the fair market value
of the stock at the time of grant. The board determines the exercise price of a
non-ISO granted under the Plan. No stock options may be granted under the Plan
after March 28, 2011, but stock options previously granted may extend beyond
that date. The exercise price may be paid in cash or by check. Subject to
certain additional limitations, the board may also permit the exercise price to
be paid by tendering shares of stock, by delivery of a promissory note, by
delivery to us of an undertaking by a broker to deliver promptly sufficient
funds to pay the exercise price, or a combination of the foregoing.

    Stock appreciation rights ("SARs") may be granted either alone or in tandem
with stock option grants. Each SAR entitles the holder on exercise to receive an
amount in cash or stock or a combination thereof (such form to be determined by
the board) determined in whole or in part by reference to appreciation in the
fair market value of a share of Stock. SARs may be based solely on appreciation
in the fair market value of stock or on a comparison of such appreciation with
some other measure of market growth.

    The Plan provides for awards of nontransferable shares of restricted stock
subject to forfeiture, as well as unrestricted shares of stock. Shares of
restricted stock may not be sold, transferred, pledged, assigned, or otherwise
alienated or hypothecated until the end of the applicable period and the
satisfaction of any other conditions or restrictions established by the board.
Except as the Plan otherwise specifically provides, if a participant ceases to
be an employee or ceases to continue the consulting or other similar
relationship engaged in by such participant with us for any reason other than
death during the restricted period, then the restricted stock must be offered to
us for purchase for the amount of cash paid for the restricted stock, or
forfeited to us if no cash was paid. The Plan also

                                       47

provides for deferred grants entitling the recipient to receive shares of stock
in the future at such times and on such conditions as the board may specify.

    The Plan provides for performance awards entitling the recipient to receive
without payment cash or stock or a combination thereof following the attainment
of performance goals determined by the board. In the case of any performance
award intended to qualify for the performance-based remuneration exception
described in Section 162(m) of the Code, the board will in writing pre-establish
specific performance goals that are based upon any one or more operational,
result or event-specific goals.

    The Plan provides that the board has full authority to decide whether to
make a loan to a participant in connection with the purchase of stock under an
award or with the payment of any applicable income tax recognized as a result of
an award. The Plan also provides that, in connection with any award, the board
may provide for and grant a cash award with certain limitations as to the amount
of the supplemental grant.

    Except as otherwise provided by the board, if a participant dies, options
and SARs exercisable immediately prior to death may be exercised by the
participant's executor, administrator or transferee during a period of one year
following such death (or for the remainder of their original term, if less).
Options and SARs not exercisable at a participant's death terminate. In the case
of termination for reasons other than death, options and SARs remain
exercisable, to the extent they were exercisable immediately prior to
termination, for three months (or for the remainder of their original term, if
less); provided that if in the Board's judgment the reason for the award
holder's termination casts discredit on us sufficient to justify immediate
termination of the award, then such award will immediately terminate.

    In the case of certain mergers, consolidations or other transactions in
which we are acquired or is liquidated and there is a surviving or acquiring
corporation, the Plan permits the board to arrange for the assumption of awards
outstanding under the Plan or the grant to participants of replacement awards by
that corporation. All outstanding awards not assumed by the surviving or
acquiring corporation shall become exercisable immediately prior to the
consummation of such merger, consolidation or other transaction and upon such
consummation all outstanding awards that have not been assumed or replaced will
terminate.

    The board may amend the Plan or any outstanding award at any time, provided
that no such amendment will, without the approval of our stockholders,
effectuate a change for which shareholder approval is required in order for the
Plan to continue to qualify for the award of ISOs under Section 422 of the Code
or for the award of performance-based compensation under Section 162(m) of the
Code.

    The future benefits or amounts that would be received under the Plan by the
executive officers and the non-executive officer employees are discretionary and
are therefore not determinable at this time.

    The 2001 Equity Incentive Plan became effective as of May 31, 2001. On
August 3, 2001, we filed a registration statement on Form S-8 covering the
shares underlying the options authorized by the 2001 Equity Incentive Plan.

                                       48

                           RELATED PARTY TRANSACTIONS

COMPENSATION PAID TO DR. SCHWARTZ

    Dr. Schwartz, a member and Chairman of the board of directors, was retained
in July 1998 under a consulting services agreement to serve as a consultant to
us rendering strategic business advice and counseling services, including
assistance in the negotiation and consummation of strategic collaboration
transactions specified by us. The consulting services agreement provided for
compensation to Dr. Schwartz in the amount of $50,000 in cash for services
rendered during the period of September 27, 1997 through July 26, 1998, plus a
fully vested option to purchase 20,000 shares of our common stock at $1.281, the
fair market value of our common stock at the time of the grant. For services
rendered during the term of the consulting services agreement, Dr. Schwartz was
entitled to total cash compensation of $120,000, an option to purchase 76,000
shares of our common stock with an exercise price equal to the closing bid price
for the shares on July 27, 1998, and an option to purchase 48,000 shares of our
common stock at the then current fair market value of our common stock on
July 27, 1999, vesting at a rate of 2,000 shares per month. In addition, the
consulting services agreement provided that in the event that, at a time when
Dr. Schwartz was not a member of the board of directors but the consulting
services agreement was still in effect, Dr. Schwartz materially participated in
the negotiation and consummation of a strategic collaboration transaction
specified by us, he would have been be entitled to receive additional
compensation equal to 3% of the transaction consideration, payable half in cash
and half in the form of an option or warrant to purchase shares of our common
stock at $.20 per share, the number of shares being calculated based on the fair
market value of our common stock ten days prior to the first public announcement
of the consummation of, the execution of a letter of intent for, or the
existence of discussions concerning the collaboration transaction. There have
been no such strategic collaboration transactions that would have given rise to
additional compensation.

    On December 19, 1998, Dr. Schwartz became a member of the board of directors
and its Chairman and his compensation for services in this capacity was provided
for under the terms of a letter agreement, which also incorporated certain
compensation provided for under the consulting services agreement. Under the
letter agreement, as amended July 1, 1999, Dr. Schwartz in his capacity as
Chairman was entitled to receive $132,000 in cash per year, plus $1,500 per
board or committee meeting and $500 per telephonic meeting. He also received an
option to acquire 40,000 shares of our common stock under the 1992 Equity
Incentive Plan, with an exercise price equal to the fair market value on the
date of the grant. The time requirement for his position was set at thirty
business days per quarter. Dr. Schwartz canceled both the letter agreement and
the consulting services agreement as of March 31, 2001. He currently continues
to serve in his position as Chairman and member of the board of directors under
the terms of the compensation policy recently approved by the directors. See
"Management--Director Compensation."

COMPENSATION PAID TO DR. WEISSMAN

    Dr. Weissman, a member of the board of directors, was retained in
September 1997 to serve as a consultant to us. Pursuant to his consulting
agreement, Dr. Weissman has agreed to provide consulting services to us and
serve on our Scientific Advisory Board. We agreed to pay Dr. Weissman $50,000
per year for his services and granted him an option to purchase 500,000 shares
of common stock for $5.25 per share, of which 31,250 shares vested at the date
of grant. Originally, the remainder of the option would have vested upon the
occurrence of certain milestones related to our stem cell research program and
in the event of certain changes of control. We agreed to amend the option on
October 27, 2000 so that the shares would become exercisable over eight years
from the original grant date or in the event of certain changes of control. We
recorded compensation expense of $823,759 during the fourth quarter of 2000 as a
result of this change in the vested portion of the option. The deferred
compensation

                                       49

expense associated with the unvested portion of the grants was recorded as
$669,116. We plan to revalue the options using the Black-Scholes method on a
quarterly basis and recognize additional compensation expense accordingly. We
also agreed in September 1997 to nominate Dr. Weissman for a position on the
board of directors. Dr. Weissman's consulting agreement contains
confidentiality, noncompetition, and assignment of invention provisions and is
for a term of fifteen years, subject to earlier termination by us for cause or
frustration of purpose and earlier termination by Dr. Weissman for good reason.
Dr. Weissman initially received no compensation as a member of the board of
directors or for attending meetings of the board or its committees or meetings
of our Scientific Advisory Board, but was reimbursed for reasonable expenses he
incurred in attending such meetings. In October 2000, we agreed with
Dr. Weissman that we would pay him the same compensation paid to other members
of the board. See "Management--Director Compensation."

PREFERRED STOCK ISSUED TO DR. WEISSMAN AND MR. LEVIN

    In April 2000, we sold 750 shares of our 6% cumulative convertible preferred
stock plus a warrant to purchase 37,500 shares of our common stock at $6.58 per
share to each of Dr. Weissman and Mr. Levin, each a director, for $750,000, for
a total of $1,500,000, on terms more favorable to us than we were able to obtain
from outside investors. The face value of the shares is convertible at the
option of the holder into common stock at $3.77 per share. The holders of the
preferred stock have liquidation rights equal to their original investments plus
accrued but unpaid dividends. Any unconverted preferred stock will be converted
into common stock on April 13, 2002. The warrants expire on April 13, 2005.

                                       50

                              SELLING STOCKHOLDER

    Millennium Partners, L.P. will be selling shares in this offering. On
June 21, 2001, we issued 457,750 shares of our common stock to Millennium. At
the same time we also issued to Millennium a callable warrant to purchase 50,352
shares of our common stock and an adjustable warrant for a number of shares to
be determined on eight dates beginning six months after the closing and then
every three months thereafter. See "Description of Capital Stock--Warrants."

    On June 21, 2001, we also entered into a registration rights agreement with
Millennium in which we agreed to register the shares of our common stock
purchased by Millennium on that date as well as those shares issuable upon
exercise of the warrants issued to Millennium on that date. We agreed to use
commercially reasonable efforts to keep the registration statement in effect for
five years, until all shares covered by the registration statement are eligible
for resale pursuant to Rule 144(k), or until Millennium and its transferees no
longer hold the shares covered by the registration statement, whichever occurs
first.

    Since August 3, 2000, we have issued to Millennium a total of 2,249,273
shares of common stock. As of July 20, 2001, Millennium held 171,839 warrants to
purchase shares of our common stock. In addition to the adjustable warrant
described above, Millennium also holds an adjustable warrant, issued August 3,
2000, that may become exercisable for additional shares of common stock. See
"Description of Capital Stock--Warrants." We agreed to register all shares of
common stock issued on August 3, 2000 or thereafter in connection with that
transaction, including shares issuable to Millennium pursuant to warrants. We
have previously registered 2,160,000 shares of common stock issued or issuable
to Millennium, including all shares underlying the August 3, 2000 adjustable
warrant as of the completion of the first two adjustment periods.

    The following table shows information regarding the beneficial ownership of
our capital stock for Millennium prior to and after this offering. We have
determined beneficial ownership in the table in accordance with the rules of the
Securities and Exchange Commission as more specifically described in the notes
below. In computing the number of shares beneficially owned by a person and the
percentage ownership of that person, we have deemed to be outstanding shares of
capital stock subject to options or warrants held by that person that are
currently exercisable or will become exercisable within 60 days of June 30,
2001. To our knowledge Millennium possesses sole voting and investment power
with respect to all shares of common stock shown as beneficially owned by it.



                                               SHARES OF COMMON STOCK                       SHARES OF COMMON STOCK
                                                 BENEFICIALLY OWNED                           BENEFICIALLY OWNED
                                               BEFORE THIS OFFERING(2)                      AFTER THIS OFFERING(4)
                                              -------------------------                    -------------------------
                                              NUMBER OF                     NUMBER OF      NUMBER OF
NAME OF BENEFICIAL OWNER                       SHARES        PERCENTAGE   SHARES OFFERED    SHARES        PERCENTAGE
------------------------                      ---------      ----------   --------------   ---------      ----------
                                                                                           
Millennium Partners, L.P.(1)................  1,803,431         7.94%        1,900,000(3)  1,295,329         5.37%


--------------------------

(1) The address of Millenium Partners, L.P. is 666 Fifth Avenue, New York, New
    York 10103.

(2) Includes 171,839 shares issuable upon exercise of warrants. Beneficial
    ownership percentage is based on: these warrants; plus 21,458,211 shares of
    our common stock outstanding as of March 31, 2001; plus 457,750 shares
    issued to Millennium on June 21, 2001; plus 622,469 shares issued upon
    exercise of a warrant by Millennium on July 19, 2001. Information on
    Millennium's beneficial ownership is based in part on a Schedule 13G/A filed
    by Millennium on February 23, 2001 and on information provided by Millennium
    as of July 20, 2001. By agreement between Millennium and us, Millennium is
    not permitted to exercise warrants if such exercise would cause its
    beneficial ownership of our common stock to exceed 9.99%.

(3) Includes 457,750 outstanding shares issued on June 21, 2001 and 50,352
    shares issuable upon exercise of a callable warrant issued on June 21, 2001.
    The remainder is an estimate of the number of shares which may become
    issuable upon exercise of the adjustable warrant issued June 21, 2001 and
    those underlying the adjustable warrant issued August 3, 2000 that have not
    previously been registered by us.

(4) Includes 121,487 shares issuable upon exercise of warrants. Beneficial
    ownership percentage is based on: these warrants; plus 21,458,211 shares of
    our common stock outstanding as of March 31, 2001; plus 622,469 shares
    issued upon exercise of a warrant by Millennium on July 19, 2001; plus
    1,900,000 shares either issued to Millennium on June 21, 2001, underlying a
    warrant issued on June 21, 2001 or deemed issuable upon exercise of the
    adjustable warrants issued on June 21, 2001 and August 3, 2000.

                                       51

                          DESCRIPTION OF CAPITAL STOCK

GENERAL MATTERS

    As of March 31, 2001, the total amount of our authorized capital stock
consisted of 45,000,000 shares of common stock, $.01 par value per share, and
1,000,000 shares of authorized preferred stock, $.01 par value per share, 2,626
of which has been designated as 6% cumulative preferred stock, to be issued from
time to time in one or more series, with such designations, powers, preferences,
rights, qualifications, limitations and restrictions as our board of directors
may determine. As of March 31, 2001, we had outstanding 21,458,211 shares of
common stock and 1,500 shares of 6% cumulative convertible preferred stock.

    As of March 31, 2001, we had 287 stockholders of record with respect to our
common stock, and we had outstanding options and warrants to purchase 3,461,105
shares of our common stock, of which 871,386 were exercisable. The following
summary of provisions of our capital stock describes all material provisions of,
but does not purport to be complete and is subject to, and qualified in its
entirety by, our restated certificate of incorporation and our amended and
restated by-laws, which are included as exhibits to the registration statement
of which this prospectus forms a part, and by the provisions of applicable law.

COMMON STOCK

    The issued and outstanding shares of common stock are, and the shares of
common stock to be issued by us in connection with the offering will be, validly
issued, fully paid and nonassessable. Holders of our common stock are entitled
to any and all dividends as such dividends are declared by the board of
directors. This right is not cumulative, and no right shall accrue to holders of
common stock by reason of the fact that dividends on said shares were not
declared in any prior period. The shares of common stock are not convertible and
the holders thereof have no preemptive or subscription rights to purchase any of
our securities. Upon liquidation, dissolution or winding up of our company, the
holders of common stock are entitled to an amount equal to $1.00 per share,
subject to the rights of the holders of the preferred stock. After payment to
the holders of the common stock of the full preferential amounts due to them,
the holders of common stock have the right to share equally in the distribution
of the entire remaining assets of the company legally available for
distribution, subject to the rights of the holders of the preferred stock. Each
outstanding share of common stock is entitled to one vote on all matters
submitted to a vote of stockholders, such voting rights to be counted together
with all other shares of capital stock having voting powers and not as a
separate class, except as otherwise required by law.

    Our common stock is traded on the Nasdaq National Market under the symbol
"STEM."

PREFERRED STOCK

    Our board of directors may from time to time direct the issuance of shares
of preferred stock in series and may, at the time of issuance, determine the
rights, preferences and limitations of each series. Shares of preferred stock of
any one series shall be identical with each other in all respects except as to
the dates from which dividends shall accrue and/or cumulate. In the event of any
liquidation, dissolution or winding up of the company, the holders of
undesignated preferred stock of each series are entitled to receive an amount
fixed by our restated certificate of incorporation or by the resolution(s) of
the board of directors providing for the issuance of such series.

    The board of directors designated 2,626 shares, $.01 par value per share, as
6% cumulative convertible preferred stock, 1,500 shares of which are issued and
outstanding. The holders of these preferred shares are entitled to receive
cumulative dividends at a per share rate of 6% of the liquidation preference of
each share, per annum accruing daily and compounding quarterly, with

                                       52

priority over payment of any dividend on common stock or any other class or
series of equity security of the company. In the event of any liquidation,
dissolution or winding up of the company, the holders of the 6% cumulative
convertible preferred stock are entitled to receive in preference to holders of
any other class or series of equity securities, an amount equal to $1,000 per
share plus (i) dividends added to the liquidation preference, (ii) all accrued
but unpaid dividends and (iii) all "Monthly Delay Payments" under a registration
rights agreement, dated April 13, 2000, by and between us and Irving Weissman
and Mark Levin. The 6% cumulative convertible preferred stock was issued
pursuant to a securities purchase agreement, dated April 13, 2000, by and
between us and Irving Weissman and Mark Levin. Each holder of the 6% cumulative
convertible preferred stock has at any time the right to convert any or all 6%
cumulative convertible preferred stock held by such holder into fully paid,
validly issued and nonassessable shares of common stock, $.01 par value per
share, at which point the rights of the holders of converted 6% cumulative
convertible preferred stock shall be treated as having become the owners of such
common stock. The affirmative vote of a majority in interest of the outstanding
6% cumulative convertible preferred stock is required for (i) any amendment,
modification or repeal of the Certificate of Designations, Certificate of
Incorporation or by-laws that may amend or change or adversely affect any of the
rights or preference of the 6% cumulative convertible preferred stock; provided,
however, that the holders of 6% cumulative convertible preferred stock who are
affiliates of the company shall not participate in such votes, and such shares
shall be deemed not to be outstanding for purposes of such votes. We have no
current intention to issue any more of our unissued, authorized shares of
undesignated preferred stock. However, the issuance of any shares of
undesignated preferred stock in the future could adversely affect the rights of
the holders of common stock.

WARRANTS

    Our warrants were issued at various times since April 13, 2000 to eight
different parties as described below.

    As of April 13, 2000, we issued to each of Irving Weissman and Mark Levin,
each a director, a warrant in connection with a Securities Purchase Agreement
dated as of April 13, 2000. Each warrant is to purchase 37,500 shares of our
common stock at an exercise price of $6.58125 per share. Each warrant is
exercisable, in whole or in part, at any time on or after April 13, 2000 and on
or prior to April 13, 2005. The exercise price is subject to adjustment for
subdivisions, combinations, stock dividends, reorganizations and various other
issuances. We may, at any time during the term of the warrant, reduce the
exercise price to any amount for any period of time deemed appropriate by our
board of directors. See "Related Party Transactions--Preferred Stock Issued to
Dr. Weissman and Mr. Levin."

    We issued a warrant to Millennium Partners L.P. on August 3, 2000, which may
entitle them to receive additional shares of common stock on eight dates
beginning six months from that date and every three months thereafter. On
August 30, 2000 we issued a second warrant to Millennium which may entitle them
to receive additional shares of common stock on eight dates beginning six months
from August 30, 2000 and every three months thereafter. On November 1, 2000, we
agreed with Millennium to cancel the adjustable warrant issued on August 30,
2000 and to decrease the number of shares for which the adjustable warrant
issued on August 3, 2000 may be exercisable. The number of additional shares
Millennium will be entitled to receive on each date will be based on the number
of shares of common stock Millennium continues to hold on each date and the
market price of our common stock over a period prior to each date. We will have
the right, under certain circumstances, to limit the number of additional shares
by purchasing part of the entitlement from Millennium. The remaining warrant is
exercisable, in whole or in part, at any time on or prior to 30 days after the
last date which may entitle Millennium to receive additional shares. This
warrant is subject to adjustment for subdivisions, combinations, stock
dividends, reorganizations and various other issuances of common stock. On
January 27, 2001, Millennium's August 3, 2000 adjustable warrant became
exercisable for

                                       53

463,369 shares of our common stock, and Millennium purchased all of those shares
for $4,634 on March 30, 2001. On April 27, 2001, the adjustable warrant became
exercisable for an additional 622,469 shares of our common stock, and Millennium
purchased all of those shares for $6,225 on July 19, 2001. On June 21, 2001,
Millennium received an additional adjustable warrant similar to the adjustable
warrant issued to Millennium on August 3, 2000. It is not currently exercisable
for shares of our common stock but may be adjusted in the future to permit
purchases of our common stock at $0.01 per share.

    Millennium also received a warrant on August 3, 2000 to purchase up to
101,587 shares of common stock at $4.725 per share, which is callable by us at
$7.875 per underlying share. On August 30, 2000 we issued an additional warrant
to purchase up to 19,900 shares of common stock at $6.03 per share which is
callable by us at $10.05 per underlying share. On June 21, 2001, Millennium
received an additional warrant to purchase 50,352 shares of our common stock at
a price per share of $4.7664. This warrant is callable by us at any time at
$7.944 per underlying share. Each callable warrant is exercisable, in whole or
in part, at any time on or after the issuance date and on or prior to the fifth
year anniversary of the issuance date. The exercise price and number of shares
are subject to adjustment for subdivisions, combinations, stock dividends,
reorganizations and various other issuances.

    On August 3, 2000 we issued a warrant to the May Davis Group and four of its
affiliates to purchase up to 100,000 shares of common stock at $5.0375 per
share.

    On May 10, 2001, in connection with our execution of a common stock purchase
agreement with Sativum Investments Limited, we issued three three-year warrants
to purchase an aggregate of 350,000 shares of our common stock at $2.38 per
share to Sativum (250,000 shares), Pacific Crest Securities Inc. (75,000 shares)
and Granite Financial Group, Inc. (25,000 shares). The shares underlying these
warrants are being registered for sale by the registration statement of which
this prospectus forms a part. The exercise price and number of shares are
subject to adjustment for subdivisions, combinations, stock dividends and
reorganizations. Pacific Crest and Granite have exercised their warrants in
full.

PROVISIONS OF DELAWARE LAW GOVERNING BUSINESS COMBINATIONS

    We are subject to the "business combination" provisions of the Delaware
General Corporation Law. In general, such provisions prohibit a publicly held
Delaware corporation from engaging in various "business combination"
transactions with any "interested stockholder" for a period of three years after
the date of the transaction in which the person became an "interested
stockholder," unless:

    - the transaction is approved by the board of directors prior to the date
      the "interested stockholder" obtained such status;

    - upon consummation of the transaction which resulted in the stockholder
      becoming an "interested stockholder," the "interested stockholder" owned
      at least 85% of the voting stock of the corporation outstanding at the
      time the transaction commenced, excluding for purposes of determining the
      number of shares outstanding those shares owned by (a) persons who are
      directors and also officers and (b) employee stock plans in which employee
      participants do not have the right to determine confidentially whether
      shares held subject to the plan will be tendered in a tender or exchange
      offer; or

    - on or subsequent to such date the "business combination" is approved by
      the board of directors and authorized at an annual or special meeting of
      stockholders by the affirmative vote of at least 66 2/3% of the
      outstanding voting stock which is not owned by the "interested
      stockholder."

    A "business combination" is defined to include mergers, asset sales and
other transactions resulting in financial benefit to a stockholder. In general,
an "interested stockholder" is a person who, together with affiliates and
associates, owns 15% or more of a corporation's voting stock or within

                                       54

three years did own 15% or more of a corporation's voting stock. The statute
could prohibit or delay mergers or other takeover or change in control attempts.

TRANSFER AGENT AND REGISTRAR

    The transfer agent and registrar for our common stock is EquiServe L.P.

                                       55

                              PLAN OF DISTRIBUTION

    We will not receive any of the proceeds from the sale by the selling
stockholder of the common stock offered hereby.

    The shares of the common stock offered hereby may be sold from time to time
by the selling stockholder, or by pledgees, donees, transferees or other
successors in interest:

    - to or through underwriters or dealers;

    - directly to one or more other purchasers;

    - through agents on a best-efforts basis; or

    - through a combination of any such methods of sale.

    Such sales may be made on one or more exchanges or in the over-the-counter
market, or otherwise at prices and at terms then prevailing or at prices related
to the then current market price, or in privately negotiated transactions. The
shares may be sold by one or more of the following:

    - a block trade in which the broker or dealer so engaged will attempt to
      sell the shares as agent but may position and resell a portion of the
      block as principal to facilitate the transaction;

    - purchases by a broker or dealer as principal and resale by such broker or
      dealer for its account pursuant to this prospectus;

    - an exchange distribution in accordance with the rules of such exchange;

    - ordinary brokerage transactions and transactions in which the broker
      solicits purchasers; and

    - privately negotiated transactions without a broker or dealer.

    In effecting sales, brokers or dealers engaged by the selling stockholder
may arrange for other brokers or dealers to participate. Brokers or dealers will
receive commissions or discounts from the selling stockholder in amounts to be
negotiated prior to the sale. In addition, any securities covered by this
prospectus which qualify for sale pursuant to Rule 144 may be sold under
Rule 144 rather than pursuant to this prospectus.

    In addition, the selling stockholder may engage in short sales and other
transactions in the common stock or derivatives thereof, and may pledge, sell,
deliver or otherwise transfer the common stock offered under this prospectus in
connection with such transactions.

    If we are notified by a selling stockholder that a material arrangement has
been entered into with a broker-dealer for the sale of shares through a block
trade, special offering, exchange distribution or secondary distribution, or a
purchase by a broker-dealer as a principal, a supplemental prospectus will be
filed listing:

    - the name of each selling stockholder and of the participating
      broker-dealer(s);

    - the number of shares involved;

    - the price at which such shares were sold;

    - the commissions paid or discounts or concessions allowed to such
      broker-dealer(s), where applicable; and

    - other facts material to the transaction.

    We have agreed to pay the cost of registering the shares covered by this
prospectus and the costs of preparing this prospectus and the registration
statement under which it is filed.

    We and the selling stockholder have agreed to indemnify one another against
certain liabilities, including liabilities arising under the Securities Act.

                                       56

                                 LEGAL MATTERS

    The validity of the shares of our common stock offered hereby will be passed
upon for us by Ropes & Gray, Boston, Massachusetts.

                                    EXPERTS

    Ernst & Young LLP, independent auditors, have audited our consolidated
financial statements at December 31, 2000 and 1999, and for each of the three
years in the period ended December 31, 2000, as set forth in their report. We
have included these financial statements in the prospectus and elsewhere in the
registration statement in reliance on Ernst & Young LLP's report, given on their
authority as experts in accounting and auditing.

                      WHERE YOU CAN FIND MORE INFORMATION

    We have filed with the SEC a registration statement on Form S-3 under the
Securities Act with respect to the common stock to be sold in this offering.
This prospectus does not contain all the information included in the
registration statement and the related exhibits and schedules. You will find
additional information about us and our common stock in the registration
statement. The registration statement and the related exhibits and schedules may
be inspected and copied at the public reference facilities maintained by the SEC
at Room 1024, Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C. 20549,
and at the public reference facilities of the SEC's Regional Offices: New York
Regional Office, Seven World Trade Center, Suite 1300, New York, New York 10048;
and Chicago Regional Office, Citicorp Center, 500 West Madison Street, Chicago,
Illinois 60661. Copies of this material may also be obtained from the Public
Reference Section of the SEC at 450 Fifth Street, N.W., Washington, D.C. 20549
at prescribed rates. You can obtain information on the operation of the public
reference facilities by calling 1-800-SEC-0330. The SEC also maintains a site on
the World Wide Web (http://www.sec.gov) that contains reports, proxy and
information statements and other information regarding registrants, including
us, that file electronically with the SEC. Statements made in this prospectus
about legal documents may not necessarily be complete and you should read the
documents which are filed as exhibits or schedules to the registration statement
or otherwise filed with the SEC.

                    INCORPORATION OF DOCUMENTS BY REFERENCE

    The SEC allows us to incorporate by reference the information we file with
it, which means that we can disclose information important to you by referring
you to those documents. The information incorporated by reference is considered
to be a part of this prospectus, and information that we later file with the SEC
will automatically update and supersede this information. Accordingly, we
incorporate by reference the following documents we filed with the SEC pursuant
to Section 13 of the Securities Exchange Act of 1934:

    - our Annual Report on Form 10-K for the year ended December 31, 2000 (filed
      April 2, 2001, as amended April 30, 2001);

    - our Quarterly Report on Form 10-Q for the quarter ended March 31, 2001
      (filed May 9, 2001);

    - our Proxy Statement for the Annual Meeting of Stockholders held on
      May 31, 2001 (filed April 30, 2001);

    - our Current Reports on Form 8-K dated May 8, 2001 (filed May 8, 2001) and
      May 14, 2001 (dated May 14, 2001);

    - the description of our common stock contained in the registration
      statement on Form 8-A filed with the SEC pursuant to Section 12 of the
      Securities Exchange Act of 1934 and all amendments thereto and reports
      filed for the purpose of updating such description; and

                                       57

    - all documents filed by us with the SEC pursuant to the Securities Exchange
      Act of 1934 after the date of this prospectus and before the offering of
      common stock is completed (other than portions of such documents described
      in paragraphs (i), (k) and (l) of Item 402 of Regulation S-K promulgated
      by the SEC).

    These documents are or will be available for inspection or copying at the
locations identified above under the caption "Where You Can Find More
Information." We will provide without charge to each person to whom this
prospectus is delivered, upon written or oral request, a copy of any and all of
the documents that have been incorporated by reference in this prospectus (other
than exhibits to those documents). You should direct requests for documents to:

    StemCells, Inc.
    3155 Porter Drive
    Palo Alto, CA 94304
    Attention: Investor Relations
    Telephone number: (650) 475-3100

                                       58

               STEMCELLS, INC. (FORMERLY CYTOTHERAPEUTICS, INC.)

                   INDEX TO CONSOLIDATED FINANCIAL STATEMENTS


                                                           
Report of Independent Auditors..............................   F-2

Consolidated Balance Sheets at December 31, 2000 and 1999...   F-3

Consolidated Statements of Operations for the years ended
  December 31, 2000, 1999 and 1998..........................   F-4

Consolidated Statements of Changes in Redeemable Common
  Stock and Stockholders' Equity for the years ended
  December 31, 2000, 1999 and 1998..........................   F-5

Consolidated Statements of Cash Flows for the years ended
  December 31, 2000, 1999 and 1998..........................   F-8

Notes to Consolidated Financial Statements..................   F-9

Condensed Consolidated Balance Sheets at March 31, 2001
  (unaudited)...............................................  F-27

Condensed Consolidated Statements of Operations for the
  three months ended March 31, 2001 and March 31, 2000
  (unaudited)...............................................  F-28

Condensed Statements of Cash Flows for the three months
  ended March 31, 2001 and March 31, 2000 (unaudited).......  F-29

Notes to Condensed Consolidated Financial Statements
  (unaudited)...............................................  F-30


                                      F-1

               REPORT OF ERNST & YOUNG LLP, INDEPENDENT AUDITORS

Stockholders and Board of Directors
StemCells, Inc.

    We have audited the accompanying consolidated balance sheets of
StemCells, Inc. (formerly CytoTherapeutics, Inc.) as of December 31, 2000 and
1999, and the related consolidated statements of operations, changes in
redeemable common stock and stockholders' equity, and cash flows for each of the
three years in the period ended December 31, 2000. These financial statements
are the responsibility of the Company's management. Our responsibility is to
express an opinion on these financial statements based on our audits.

    We conducted our audits in accordance with auditing standards generally
accepted in the United States. Those standards require that we plan and perform
the audit to obtain reasonable assurance about whether the financial statements
are free of material misstatement. An audit includes examining, on a test basis,
evidence supporting the amounts and disclosures in the financial statements. An
audit also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.

    In our opinion, the financial statements referred to above present fairly,
in all material respects, the consolidated financial position of
StemCells, Inc. at December 31, 2000 and 1999, and the consolidated results of
its operations and its cash flows for each of the three years in the period
ended December 31, 2000, in conformity with accounting principles generally
accepted in the United States.

    As discussed in Note 1 to the consolidated financial statements, the Company
changed its method of accounting for the beneficial conversion of preferred
shares.

                                          /s/ ERNST & YOUNG LLP

Palo Alto, California
February 23, 2001

                                      F-2

                                STEMCELLS, INC.

                          CONSOLIDATED BALANCE SHEETS



                                                                      DECEMBER 31,
                                                              -----------------------------
                                                                  2000            1999
                                                              -------------   -------------
                                                                        
ASSETS
Current assets:
  Cash and cash equivalents.................................  $   6,068,947   $   4,760,064
  Short-term restricted investments.........................     16,356,334              --
  Accrued interest receivable...............................         16,725          42,212
  Technology sale receivable................................             --       3,000,000
  Debt service fund.........................................             --         609,905
  Other current assets......................................        524,509         558,674
                                                              -------------   -------------
Total current assets........................................     22,966,515       8,970,855

Property held for sale......................................      3,203,491       3,203,491
Property, plant and equipment, net..........................      1,451,061       1,747,885
Other assets, net...........................................      2,173,912       1,858,768
                                                              -------------   -------------
Total assets................................................  $  29,794,979   $  15,780,999
                                                              =============   =============

LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable..........................................  $     526,191   $     631,315
  Accrued expenses..........................................        837,358         970,546
  Accrued wind-down costs...................................      1,780,579       1,634,522
  Current maturities of capital lease obligations...........        332,083         324,167
                                                              -------------   -------------
Total current liabilities...................................      3,476,211       3,560,550
Capital lease obligations, less current maturities..........      2,605,000       2,937,083
Deposits....................................................         26,000          26,000
Deferred rent...............................................        705,746         502,353
Commitments
Redeemable common stock, $.01 par value; 524,337 shares
  issued and outstanding at December 31, 1999, none at
  December 31, 2000.........................................             --       5,248,610
Stockholders' equity:
  Convertible Preferred Stock, $.01 par value; 1,000,000
    shares authorized, 2,626 designated as 6% Cumulative
    Convertible Preferred Stock 1,500 shares issued and
    outstanding at December 31, 2000, none at December 31,
    1999....................................................      1,500,000              --
  Common stock, $.01 par value; 45,000,000 shares
    authorized; 20,956,887 and 18,635,565 shares issued and
    outstanding at December 31, 2000 and 1999,
    respectively............................................        209,569         186,355
  Additional paid-in capital................................    138,150,067     123,917,758
  Accumulated deficit.......................................   (130,498,187)   (119,372,710)
  Accumulated other comprehensive income....................     16,356,334              --
  Deferred compensation.....................................     (2,735,761)     (1,225,000)
                                                              -------------   -------------
Total stockholders' equity..................................     22,982,022       3,506,403
                                                              -------------   -------------
Total liabilities and stockholders' equity..................  $  29,794,979   $  15,780,999
                                                              =============   =============


          SEE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS.

                                      F-3

                                STEMCELLS, INC.

                     CONSOLIDATED STATEMENTS OF OPERATIONS



                                                               YEAR ENDED DECEMBER 31,
                                                      ------------------------------------------
                                                          2000           1999           1998
                                                      ------------   ------------   ------------
                                                                           
Revenue from collaborative and licensing
  agreements........................................  $     74,300   $  5,021,707   $  8,803,163

Operating expenses:
  Research and development..........................     5,979,007      9,984,027     17,658,530
  General and administrative........................     3,361,231      4,927,303      4,602,758
  Encapsulated Cell Therapy wind-down and corporate
    relocation......................................     3,327,360      6,047,806             --
                                                      ------------   ------------   ------------
                                                        12,667,598     20,959,136     22,261,288
                                                      ------------   ------------   ------------

Loss from operations................................   (12,593,298)   (15,937,429)   (13,458,125)

Other income (expense):
  Interest income...................................       303,746        564,006      1,253,781
  Interest expense..................................      (272,513)      (335,203)      (472,400)
  Gain on sale of Investment........................     1,427,686             --             --
  Other income......................................         8,902             --         48,914
                                                      ------------   ------------   ------------
                                                         1,467,821        228,803        830,295
                                                      ------------   ------------   ------------

Net loss............................................  $(11,125,477)  $(15,708,626)  $(12,627,830)
Deemed dividend to preferred shareholders...........      (265,000)            --             --
                                                      ------------   ------------   ------------
Net loss applicable to common shareholders before a
  cumulative effect of a change in accounting
  principle.........................................  $(11,390,477)  $(15,708,626)  $(12,627,830)

Cumulative effect of a change in accounting
  principle due to deemed dividend..................  $   (216,000)  $         --   $         --
                                                      ------------   ------------   ------------
Net loss applicable to common shareholders..........  $(11,606,477)  $(15,708,626)  $(12,627,830)
                                                      ============   ============   ============
Basic and diluted net loss per share applicable to
  common shareholders before cumulative effect......  $       (.57)  $       (.84)  $       (.69)
Cumulative effect of a change in accounting
  principle.........................................  $       (.01)            --             --
                                                      ------------   ------------   ------------
Basic and diluted net loss per share applicable to
  common shareholders...............................  $       (.58)  $       (.84)  $       (.69)

Shares used in computing basic and diluted net loss
  per share.........................................    20,067,760     18,705,838     18,290,548
                                                      ============   ============   ============


          SEE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS.

                                      F-4

                                STEMCELLS, INC.
CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE COMMON STOCK AND STOCKHOLDERS'
                                     EQUITY


                                          REDEEMABLE                                                                 ACCUMULATED
                                         COMMON STOCK            COMMON STOCK         ADDITIONAL                        OTHER
                                     ---------------------   ---------------------     PAID-IN       ACCUMULATED    COMPREHENSIVE
                                      SHARES      AMOUNT       SHARES      AMOUNT      CAPITAL         DEFICIT      INCOME (LOSS)
                                     --------   ----------   ----------   --------   ------------   -------------   --------------
                                                                                               
Balances, December 31, 1997........  557,754    $5,583,110   17,526,220   $175,262   $121,472,844   $ (91,036,254)     $(8,877)
Issuance of common stock under the
  stock purchase plan..............       --            --       43,542        436         83,622
Common stock issued pursuant to
  employee benefit plan............       --            --       84,812        848        143,025              --           --
Issuance of common
  stock--StemCells.................       --            --      101,320      1,013        505,587              --           --
Redeemable common stock lapses.....  (33,417)     (334,500)      33,417        334        334,166              --           --
Exercise of stock options..........       --            --       11,012        110          1,254              --           --
Deferred compensation--amortization
  and cancellations................       --            --           --         --        321,108              --           --
Change in unrealized losses on
  marketable securities............       --            --           --         --             --              --        3,679
Net loss...........................       --            --           --         --             --     (12,627,830)          --
Comprehensive loss.................
                                     -------    ----------   ----------   --------   ------------   -------------      -------
Balances, December 31, 1998........  524,337     5,248,610   17,800,323    178,003    122,861,606    (103,664,084)      (5,198)



                                                         TOTAL
                                       DEFERRED      STOCKHOLDERS'
                                     COMPENSATION       EQUITY
                                     -------------   -------------
                                               
Balances, December 31, 1997........   $(1,702,820)   $ 28,900,155
Issuance of common stock under the
  stock purchase plan..............                        84,058
Common stock issued pursuant to
  employee benefit plan............            --         143,873
Issuance of common
  stock--StemCells.................            --         506,600
Redeemable common stock lapses.....            --         334,500
Exercise of stock options..........            --           1,364
Deferred compensation--amortization
  and cancellations................       229,901         551,009
Change in unrealized losses on
  marketable securities............            --           3,679
Net loss...........................            --     (12,627,830)
                                                     ------------
Comprehensive loss.................                   (12,624,151)
                                      -----------    ------------
Balances, December 31, 1998........    (1,472,919)     17,897,408


                                      F-5

                                STEMCELLS, INC.
CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE COMMON STOCK AND STOCKHOLDERS'
                               EQUITY (CONTINUED)


                                          REDEEMABLE                                                                 ACCUMULATED
                                         COMMON STOCK            COMMON STOCK         ADDITIONAL                        OTHER
                                     ---------------------   ---------------------     PAID-IN       ACCUMULATED    COMPREHENSIVE
                                      SHARES      AMOUNT       SHARES      AMOUNT      CAPITAL         DEFICIT      INCOME (LOSS)
                                     --------   ----------   ----------   --------   ------------   -------------   --------------
                                                                                               
Balances, December 31, 1998........  524,337    $5,248,610   17,800,323   $178,003   $122,861,606   $(103,664,084)     $(5,198)
Issuance of common stock...........       --            --      196,213   $  1,962   $    318,221              --           --
Issuance of common stock under the
  stock purchase plan..............       --            --       57,398        574         41,619
Common stock issued pursuant to
  employee benefit plan............       --            --       90,798        908        102,502              --           --
Exercise of stock options..........       --            --      490,833      4,908        513,534              --           --
Deferred compensation--amortization
  and cancellations................       --            --           --         --         80,276              --           --
Change in unrealized losses on
  marketable securities............       --            --           --         --             --              --        5,198
Net loss...........................       --            --           --         --             --     (15,708,626)          --
Comprehensive loss.................
                                     -------    ----------   ----------   --------   ------------   -------------      -------
Balances, December 31, 1999........  524,337     5,248,610   18,635,565    186,355    123,917,758    (119,372,710)          --



                                                         TOTAL
                                       DEFERRED      STOCKHOLDERS'
                                     COMPENSATION       EQUITY
                                     -------------   -------------
                                               
Balances, December 31, 1998........   $(1,472,919)   $ 17,897,408
Issuance of common stock...........            --    $    320,183
Issuance of common stock under the
  stock purchase plan..............                        42,193
Common stock issued pursuant to
  employee benefit plan............            --         103,410
Exercise of stock options..........            --         518,442
Deferred compensation--amortization
  and cancellations................       247,919         328,195
Change in unrealized losses on
  marketable securities............            --           5,198
Net loss...........................            --     (15,708,626)
Comprehensive loss.................                   (15,703,428)
                                      -----------    ------------
Balances, December 31, 1999........    (1,225,000)      3,506,403


                                      F-6

                                STEMCELLS, INC.
CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE COMMON STOCK AND STOCKHOLDERS'
                               EQUITY (CONTINUED)


                                      REDEEMABLE
                                        COMMON
                                        STOCK               PREFERRED STOCK          COMMON STOCK         ADDITIONAL
                                ----------------------   ---------------------   ---------------------     PAID-IN
                                 SHARES      AMOUNT       SHARES      AMOUNT       SHARES      AMOUNT      CAPITAL
                                --------   -----------   --------   ----------   ----------   --------   ------------
                                                                                    
Balances, December 31, 1999...   524,337   $ 5,248,610       --             --   18,635,565   $186,355   $123,917,758
  Issuance of common stock to
    Millennium Partners LP,
    net of issuance costs of
    $598,563..................        --            --       --             --    1,104,435   $ 11,044   $  4,390,393
Issuance of common stock
  related to license
  agreements..................        --            --       --             --       77,800   $    778   $    364,222
Common stock issued pursuant
  to employee benefit plan....        --            --       --             --        6,672   $     68   $     27,112
  Exercise of employee stock
    options...................        --            --       --             --      608,078   $  6,081   $    651,828
Redeemable common stock
  conversion..................  (524,337)  $(5,248,610)      --             --      524,337   $  5,243   $  5,243,367
Issuance of preferred stock...        --            --    1,500     $1,500,000           --         --             --
Deferred
  compensation--amortization
  and cancellations...........        --            --       --             --           --         --   $  3,555,387
Unrealized gain on short-term
  restricted investments......        --            --       --             --           --         --             --
Net loss......................        --            --       --             --           --         --             --
  Comprehensive Income........
                                --------   -----------    -----     ----------   ----------   --------   ------------
Balances, December 31, 2000...        --            --    1,500     $1,500,000   20,956,887   $209,569   $138,150,067
                                ========   ===========    =====     ==========   ==========   ========   ============



                                                 ACCUMULATED
                                                    OTHER                            TOTAL
                                 ACCUMULATED    COMPREHENSIVE      DEFERRED      STOCKHOLDERS'
                                   DEFICIT      INCOME (LOSS)    COMPENSATION       EQUITY
                                -------------   --------------   -------------   -------------
                                                                     
Balances, December 31, 1999...  $(119,372,710)   $        --      $(1,225,000)   $  3,506,403
  Issuance of common stock to
    Millennium Partners LP,
    net of issuance costs of
    $598,563..................             --             --               --    $  4,401,437
Issuance of common stock
  related to license
  agreements..................             --             --               --    $    365,000
Common stock issued pursuant
  to employee benefit plan....             --             --               --    $     27,180
  Exercise of employee stock
    options...................             --             --               --    $    657,909
Redeemable common stock
  conversion..................             --             --               --    $  5,248,610
Issuance of preferred stock...             --             --               --    $  1,500,000
Deferred
  compensation--amortization
  and cancellations...........             --             --      $(1,510,760)   $  2,044,627
Unrealized gain on short-term
  restricted investments......             --    $16,356,334               --    $ 16,356,334
Net loss......................  $ (11,125,477)            --               --    $(11,125,477)
                                                                                 ------------
  Comprehensive Income........                                                   $  5,230,858
                                -------------    -----------      -----------    ------------
Balances, December 31, 2000...  $(130,498,187)   $16,356,334      $(2,735,761)   $ 22,982,022
                                =============    ===========      ===========    ============


SEE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

                                      F-7

                                STEMCELLS, INC.

                     CONSOLIDATED STATEMENTS OF CASH FLOWS



                                                                       YEAR ENDED DECEMBER 31,
                                                              ------------------------------------------
                                                                  2000           1999           1998
                                                              ------------   ------------   ------------
                                                                                   
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss....................................................  $(11,125,477)  $(15,708,626)  $(12,627,830)
Adjustments to reconcile net loss to net cash used in
  operating activities:
    Depreciation and amortization...........................       738,593      1,717,975      2,244,146
    Acquired research and development.......................            --             --        551,009
    Amortization of deferred compensation...................     2,044,627        328,195             --
    Fair market adjustment for property held for sale.......                      300,000
    Other non-cash charges..................................                      320,183        410,173
    Gain on investment......................................    (1,427,686)            --             --
    Loss on sale of property, plant and equipment...........            --      1,117,286             --
    Loss on sale of intangibles.............................            --        440,486             --
    Changes in operating assets and liabilities:
      Accrued interest receivable...........................        25,488        164,397        346,577
      Technology receivable.................................     3,000,000             --             --
      Other current assets..................................       315,213        283,000       (265,665)
      Accounts payable and accrued expenses.................       (92,255)     1,344,142     (2,378,613)
      Deferred rent.........................................       203,393        279,680             --
      Deferred revenue......................................            --     (2,500,000)     2,483,856
                                                              ------------   ------------   ------------
Net cash used in operating activities.......................    (6,318,104)   (11,913,282)    (9,236,347)

CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sale of Investments...........................     1,427,686             --             --
Purchases of marketable securities..........................                   (4,397,676)   (18,982,387)
Proceeds from sales of marketable securities................                   13,923,813     22,573,625
Purchases of property, plant and equipment..................      (151,212)      (192,747)    (2,153,525)
Proceeds on sale of fixed assets............................            --        746,448             --
Acquisition of other assets.................................      (886,751)      (558,311)      (400,219)
Disposal of other assets....................................            --        440,486             --
                                                              ------------   ------------   ------------
Net cash provided by investing activities...................       389,723      9,962,013      1,037,494

CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock......................     4,401,437        145,603        227,931
Proceeds from the exercise of stock options.................       685,089        518,442          1,364
Common stock issued for agreements..........................       365,000             --             --
Proceeds from issuance of preferred stock...................     1,500,000             --             --
Proceeds from debt financings...............................            --             --      1,259,300
Change in debt service fund.................................       609,905             --             --
Repayments of debt and lease obligations....................      (324,167)    (1,817,500)    (1,366,655)
                                                              ------------   ------------   ------------
Net cash provided by (used in) financing activities.........     7,237,264     (1,153,455)       121,940
                                                              ------------   ------------   ------------
Increase (decrease) in cash and cash equivalents............     1,308,883     (3,104,724)    (8,076,913)
Cash and cash equivalents at beginning of year..............     4,760,064      7,864,788     15,941,701
                                                              ------------   ------------   ------------
Cash and cash equivalents at end of the year................  $  6,068,947   $  4,760,064   $  7,864,788
                                                              ============   ============   ============

Supplemental disclosure of cash flow information:
Interest paid...............................................  $    272,513   $    335,203   $    444,047


          SEE ACCOMPANYING NOTES TO CONSOLIDATED FINANCIAL STATEMENTS.

                                      F-8

                                STEMCELLS, INC.

                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

                               DECEMBER 31, 2000

1.  NATURE OF BUSINESS

    StemCells, Inc. (the "Company") is a biopharmaceutical company that operates
in one segment, engaged in the development of novel stem cell therapies designed
to treat human diseases and disorders. On May 23, 2000, the Company's name was
changed to Stem Cells, Inc. from CytoTherapeutics, Inc. by vote of the
shareholders at the Annual Meeting.

    As of December 31, 2000, the Company had cash and cash equivalents of
approximately $6.1 million and a restricted short-term equity investment of
approximately $16.4 million in Modex Therapeutics, a Swiss Biotherapeutics
company. Since inception, the Company has incurred annual losses and negative
cash flows from operations and has an accumulated deficit of approximately
$130.5 million at December 31, 2000. The Company has not derived any revenues
from the sale of any products, and does not expect to receive revenues from
product sales for at least several years. As a result, the Company is dependent
upon external financing from equity and debt offerings and revenues from
collaborative research arrangements with corporate sponsors to finance its
operations. There are no such collaborative research arrangements at this time
and there can be no assurance that such financing or partnering revenues will be
available when needed or on terms acceptable to the Company.

    As noted above, the Company has a restricted investment in Modex
Therapeutics, a Swiss Biotherapeutics company with a fair market value of
approximately $16.4 million at December 31, 2000. On January 9, 2001, the
Company sold 22,616 shares of Modex common stock for total proceeds of
approximately $2.5 million. The Company is restricted from selling any of the
remaining 103,577 shares until April 12, 2001. The value of the Company's
holdings is subject to market risk and foreign currency fluctuation and could
decrease significantly. The Company is currently in discussions with Modex to
sell the remaining shares during 2001. If the Company decided to sell the Modex
shares, due to relatively small trading volume in Modex shares and the
relatively large size of the Company holdings, or other factors, the Company may
not be able to sell its Modex shares at their market value or at all, and the
Company may have to sell these shares at a significant discount to the market
price.

    If the Company is unable to obtain the necessary proceeds from the sale of
Modex shares, significant reductions in spending and the delay or cancellation
of planned activities may be necessary. In such event, the Company intends to
implement expense reduction plans in a timely manner to enable the Company to
meet its operating cash requirements through December 31, 2001.

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

PRINCIPLES OF CONSOLIDATION

    The consolidated financial statements include accounts of the Company and
StemCells California, Inc., a wholly owned subsidiary. Significant intercompany
accounts have been eliminated in consolidation.

USE OF ESTIMATES

    The preparation of the consolidated financial statements in conformity with
accounting principles generally accepted in the United States, that requires
management to make estimates and assumptions that affect the amounts reported in
the consolidated financial statements and accompanying notes. Actual results
could differ from those estimates.

                                      F-9

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
CASH EQUIVALENTS AND INVESTMENTS

    Cash equivalents include funds held in investments with original maturities
of three months or less when purchased. The Company's policy regarding selection
of investments, pending their use, is to ensure safety, liquidity, and capital
preservation while obtaining a reasonable rate of return.

    The Company determines the appropriate classification of securities at the
time of purchase and reevaluates such designation as of each balance sheet date.
The Company classifies such holdings as available-for-sale securities, which are
carried at fair value, with unrealized gains and losses reported as a separate
component of stockholders' equity.

COMPREHENSIVE INCOME (LOSS)

    Comprehensive income (loss) is comprised of net income (loss) and other
comprehensive income (loss). The only component of other comprehensive income
(loss) is unrealized gains and losses on our available-for-sale securities.
Comprehensive income (loss) has been disclosed in the statement of changes in
redeemable common stock and stockholders' Equity.

PROPERTY, PLANT AND EQUIPMENT

    As a result of the Company's decision to exit the encapsulated cell
technology and relocate its corporate headquarters to Sunnyvale, California,
certain property considered by management to no longer be necessary has been
made available for sale or lease. The aggregate carrying value of such property
has been reviewed by management, subject to appraisal and adjusted downward to
estimated market value.

    Property, plant and equipment, including that held under capital lease
obligations, is stated at cost and depreciated using the straight-line method
over the estimated life of the respective asset, or the lease term if shorter,
as follows:


                                                           
Building and improvements...................................  3 - 15 years
Machinery and equipment.....................................  3 - 10 years
Furniture and fixtures......................................  3 - 10 years


PATENT AND LICENSE COSTS

    The Company capitalizes certain patent costs related to patent applications.
Accumulated costs are amortized over the estimated economic life of the patents,
not to exceed 17 years, using the straight-line method, commencing at the time
the patent is issued. Costs related to patent applications are charged to
expense at the time such patents are deemed to have no continuing value. At
December 31, 2000 and 1999, total costs capitalized were $638,000 and $718,000
and the related accumulated amortization were $9,000 and $9,000, respectively.
Patent expense totaled $305,000, $539,000, and $3,000 in 2000, 1999 and 1998,
respectively.

    In December 1999 the Company sold its Encapsulated Cell Technology ("ECT")
to Neurotech, S.A. for an initial payment of $3,000,000, which was paid in 2000,
royalties on future product sales, and a portion of certain Neurotech revenues
from third parties in return for the assignment to Neurotech

                                      F-10

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
of intellectual property assets relating to ECT. In addition, the Company
retained certain non-exclusive rights to use ECT in combination with its
proprietary stem cell technology and in the field of vaccines for prevention and
treatment of infectious diseases. The patent portfolio that was sold had a net
book value of $3,180,000. In year 2000 the Company received $74,300 representing
a portion of revenues received by Neurotech from third parties.

STOCK BASED COMPENSATION

    The Company grants qualified stock options for a fixed number of shares to
employees with an exercise price equal to the fair market value of the shares at
the date of grant. The Company accounts for stock option grants in accordance
with APB Opinion No. 25, ACCOUNTING FOR STOCK ISSUED TO EMPLOYEES, and,
accordingly, recognizes no compensation expense for qualified stock option
grants.

    For certain non-qualified stock options granted to non-employees, the
Company accounts for these grants in accordance with FAS No. 123--ACCOUNTING FOR
STOCK-BASED COMPENSATION AND EITF96-18--ACCOUNTING FOR EQUITY INSTRUMENTS THAT
ARE ISSUED TO OTHER THAN EMPLOYEES FOR ACQUIRING, OR IN CONJUNCTION WITH
SELLING, GOODS OR SERVICES, and accordingly, recognizes as consulting expenses
the estimated fair value of such options as calculated using the Black-Scholes
valuation model, and is remeasured during the vesting period. Fair value is
determined using methodologies allowable by FAS No. 123. The cost is amortized
over the vesting period of each option or the recipient's contractual
arrangement, if shorter.

LONG LIVED ASSETS

    The Company routinely evaluates the carrying value of its long-lived assets.
The Company records impairment losses on long-lived assets used in operations
when events and circumstances indicate that assets may be impaired and the
undiscounted cash flows estimated to be generated by the assets are less than
the carrying amount of those assets. If an impairment exists, the charge to
operations is measured as the excess of the carrying amount over the fair value
of the assets.

INCOME TAXES

    The liability method is used to account for income taxes. Deferred tax
assets and liabilities are determined based on differences between financial
reporting and income tax bases of assets and liabilities as well as net
operating loss carry forwards and are measured using the enacted tax rates and
laws that are expected to be in effect when the differences reverse. Deferred
tax assets may be reduced by a valuation allowance to reflect the uncertainty
associated with their ultimate realization.

REVENUE RECOGNITION

    Revenues from collaborative agreements are recognized as earned upon either
the incurring of reimbursable expenses directly related to the particular
research plan or the completion of certain development milestones as defined
within the terms of the collaborative agreement. Payments received in advance of
research performed are designated as deferred revenue. StemCells recognizes
non-refundable upfront license fees and certain other related fees on a
straight-line basis over the development period. Fees associated with
substantive at risk, performance milestones are recognized as revenue upon their
completion, as defined in the respective agreements.

                                      F-11

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

2.  SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
RECENT ACCOUNTING PRONOUNCEMENTS

    In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
"Accounting for Derivative Instruments and Hedging Activities" (SFAS 133), which
establishes accounting and reporting standards for derivative instruments,
including certain derivative instruments embedded in other contracts, and for
hedging activities. In June 1999, the FASB issued SFAS No. 137, "Accounting for
Derivative Instruments and Hedging Activities--Deferral of the Effective Date of
FASB Statement No. 133." The Company is required to adopt SFAS 133 effective
January 1, 2001. Because the Company does we does not hold any derivative
instruments and does not engage in hedging activities, management does not
believe the adoption of SFAS 133 will have an impact on our financial position
or results of operations.

    In November 2000, the FASB issued Emerging Issues Task Force Issue No.
00-27, "Application of EITF Issue No. 98-5, Accounting for Convertible
Securities with Beneficial Conversion Features or Contingently Adjustable
Conversion Ratios, to Certain Convertible Instruments" ("EITF 00-27") which is
effective retroactively to September 1999 for all such instruments. EITF 00-27
clarifies the accounting for instruments with beneficial conversion features or
contingently adjustable conversion ratios. According to the new accounting
principle, the beneficial conversion features should be calculated by first
allocating the proceeds received from the financing among the convertible
instrument and the detachable warrants and then, measuring the beneficial
conversion feature between the stated conversion price of the convertible
instrument and the effective conversion price based on the allocated proceeds.
Previously, the beneficial conversion feature calculation was based on the
difference between the stated conversion price of the convertible instrument and
the fair value of the Company's stock price on the closing date of the
financing. As a result of the new accounting principle, the Company modified the
calculation of the beneficial conversion features associated with its 6%
cumulative convertible preferred stock.

    The Company has presented the effect of adopting the new accounting
principle as a cumulative effect of a change in accounting principle as allowed
for in EITF 00-27. Accordingly, the Company has recognized an additional
$216,000 of deemed dividend on preferred stock.

RESEARCH AND DEVELOPMENT COSTS

    The Company expenses all research and development costs as incurred.

NET LOSS PER SHARE

    Basic and diluted net loss per share has been computed using the
weighted-average number of shares of common stock outstanding during the period,
less shares subject to repurchase. The Company has excluded outstanding stock
options and warrants, and shares subject to repurchase from the calculation of
diluted loss per common share because all such securities are anti-dilutive for
all applicable periods presented.

3.  WIND-DOWN OF ENCAPSULATED CELL TECHNOLOGY RESEARCH AND DEVELOPMENT PROGRAM

    Until mid-1999, the Company engaged in research and development in
encapsulated cell therapy technology, including a pain control program funded by
AstraZeneca Group plc. The results from the

                                      F-12

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

3.  WIND-DOWN OF ENCAPSULATED CELL TECHNOLOGY RESEARCH AND DEVELOPMENT PROGRAM
(CONTINUED)
85-patient double-blind, placebo-controlled trial of our encapsulated bovine
cell implant for the treatment of severe, chronic pain in cancer patients did
not, however, meet the criteria AstraZeneca had established for continuing
trials for the therapy, and in June 1999 AstraZeneca terminated the
collaboration, as allowed under the terms of the original collaborative
agreement signed in 1995.

    As a result of termination, management determined in July 1999 to
restructure its research operations to abandon all further encapsulated cell
technology research and concentrate its resources on the research and
development of its proprietary platform of stem cell technologies.

    The Company wound down its research and manufacturing operations in Lincoln,
Rhode Island, and relocated its remaining research and development activities,
and its corporate headquarters, to the facilities of its wholly owned
subsidiary, StemCells California, Inc., in Sunnyvale, California, in
October 1999. The Company terminated legal, professional and consulting
contractual arrangements in support of ECT research. The Company had used these
legal, professional and consulting contractual arrangements to meet regulatory
requirements in support of its research work, to support contractual
arrangements with clinical sites, to provide assistance at clinical sites in
administrating therapy and documenting activities, and to assist in compliance
with FDA and other regulations regarding its clinical trials. ECT related patent
law work was also terminated. The Company also engaged professional consultants
in connection with the determination to exit its ECT activities and restructure
its operations, which concluded with the exit from ECT activities and relocation
of its corporate headquarters to California. The Company reduced its workforce
by approximately 58 employees who had been focused on ECT programs and 10
administrative employees. As a result, the Company sold excess furniture and
equipment in December 1999 and is seeking to sublease the science and
administrative facility and to sell the pilot manufacturing facility.

    Wind-down expenses totaled $3,327,360 and $6,047,806, for the year ended
December 31, 2000 and 1999, respectively. No such expenses were incurred in
1998. These expenses relate to the wind-down of our encapsulated cell technology
research and other Rhode Island operations and the transfer of the corporate
headquarters to Sunnyvale, California. Expenses for the year 2000, includes an
accrual for the estimated lease and facility costs related to the facilities in
Rhode Island through 2001. Expenses for the year 1999 also includes an accrual
for the estimate of the costs of settlement of a 1989 funding agreement with the
Rhode Island Partnership for Science and Technology ("RIPSAT").

    At December 31, 1999, the Company's $1.6 million wind-down reserve included
approximately $1.2 million for the RIPSAT settlement and approximately
$0.4 million for Rhode Island facility for the estimated lease payments and
operating costs of the Rhode Island facilities through an expected disposal date
of June 30, 2000. In 2000 the Company settled with RIPSAT, paid $1.2 million and
paid 0.4 million related to Rhode Island facilities. The Company did not sublet
the Rhode Island facilities in 2000 and therefore made a change in estimate to
accrue additional expenses of $3.3 million to cover operating lease payments,
utilities, taxes, insurance, maintenance, interest and other non-employee
expenses through 2001. At December 31, 2000 the remaining wind-down reserve
totaled $1.7 million.

                                      F-13

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

3.  WIND-DOWN OF ENCAPSULATED CELL TECHNOLOGY RESEARCH AND DEVELOPMENT PROGRAM
(CONTINUED)
    A description of wind-down expenses, including the amounts and periods of
recognition, are as follows:



                                                 YEAR ENDED          YEAR ENDED
                                              DECEMBER 31, 1999   DECEMBER 31, 2000
                                              -----------------   -----------------
                                                            
Employee severance costs....................     $1,554,000
Impairment losses(1):
  Fixed assets..............................        800,000
  ECT patents...............................        260,000
                                                 ----------
                                                  1,060,000
Rhode Island facilities carrying costs(2):
  Corporate headquarters....................        702,000          $3,327,000
  PILOT MANUFACTURING PLANT.................        562,000
                                                 ----------
                                                  1,264,000           3,327,000
EMPLOYEE OUTPLACEMENT.......................        200,000
RIPSAT settlement(3)........................      1,172,000
Loss on sale of assets(4):
  Fixed assets..............................        318,000
  ECT patents...............................        180,000
                                                 ----------
                                                    498,000
Write-down of pilot plant(5)................        300,000
                                                 ----------
                                                 $6,048,000          $3,327,000
                                                 ==========          ==========


------------------------

(1) Management's estimate of the fixed asset impairment was derived from
    communications with an outside auction house. The patent impairment loss was
    based on preliminary negotiations with parties interested in acquiring the
    patents.

(2) Facilities carrying costs include operating lease payments, utilities,
    property taxes, insurance, maintenance, interest and other non-employee
    related expenses necessary to maintaining these facilities through the
    expected date of disposition (December 31, 2001)

(3) The Company originally received funding from the Rhode Island Partnership
    for Science and Technology (RIPSAT) for purposes of conducting ECT
    activities conditioned upon maintaining the operation within the state.
    RIPSAT claimed that the Company's decision to exit ECT activities and close
    the Rhode Island operation was in violation of the funding arrangement and
    that the Company was obligated to return a portion of the funding proceeds.
    Although the Company disputed these claims, during the fourth quarter of
    1999, management determined it was in the best interest of the Company to
    settle the issue.

(4) The Company held an auction to sell all ECT fixed assets. Proceeds from that
    sale resulted in a loss, which was related to machinery and equipment
    ($292,000), and furniture and fixtures ($26,000).

(5) The write-down of the pilot plant was based on an independent property
    appraisal.

                                      F-14

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

3.  WIND-DOWN OF ENCAPSULATED CELL TECHNOLOGY RESEARCH AND DEVELOPMENT PROGRAM
(CONTINUED)
    Property held for sale at December 31, 2000 and 1999, consisted of
$3.2 million relating to the Company's pilot plant facility located in Lincoln,
Rhode Island. The company suspended depreciation of these assets in 1999. The
balance reflected the $300,000 write-down included as part of the additional
wind-down expenses recognized in accordance with Financial Accounting Standards
Board Statement 121, which requires that long-lived assets be reviewed for
impairment whenever events or circumstances indicate that the carrying value of
the asset may not be recoverable. There were no such assets at December 31,
1998.

4.  STEMCELLS CALIFORNIA, INC.

    In September 1997, a merger of a wholly owned subsidiary of the company and
StemCells California, Inc. was completed. As part of the acquisition of
StemCells, Richard M. Rose, M.D., became President, Chief Executive Officer and
director of the Company and Dr. Irving Weissman became a director of the
Company. Upon consummation of the merger, the Company entered into consulting
arrangements with the principal scientific founders of StemCells: Dr. Irving
Weissman, Dr. Fred H. Gage and Dr. David Anderson. Additionally, in connection
with the merger, the Company was granted an option by the former shareholders of
StemCells to repurchase 500,000 of the Company's shares of Common Stock
exchanged for StemCells shares, upon the occurrence of certain events. To
attract and retain Drs. Rose, Weissman, Gage and Anderson, and to expedite the
progress of the Company's stem cell program, the Company awarded these
individuals options to acquire a total of approximately 1.6 million shares of
the Company's common stock, at an exercise price of $5.25 per share, the quoted
market price at the grant date. The Company also designated a pool of 400,000
options to be granted to persons in a position to make a significant
contribution to the success of the stem cell program. Under the original grants,
approximately 100,000 of these options were exercisable immediately on the date
of grant, 1,031,000 of these options would vest and become exercisable only upon
the achievement of specified milestones related to the Company's stem cell
development program and the remaining 468,750 options would vest over eight
years. In connection with the 468,750 options issued to a non-employee,
Dr. Anderson, the Company recorded deferred compensation of $1,750,000, the fair
value of such options at the date of grant, which will be amortized over an
eight-year period. The fair value was determined using the Black-Scholes method.

    Effective October 31, 2000, the Company agreed with Drs. Weissman and Gage
to revise their 468,750 milestone-vesting stock options to time-based vesting,
on the same schedule as Dr. Anderson's option. Under each of the revised
options, 168,750 shares vested immediately, and the remaining 300,000 shares
will vest at 50,000 per year on September 25, until September 25, 2005, when the
final 100,000 shares will vest. The exercise price remains $5.25 per share. The
Company recorded $1,647,000 as compensation expense for the fair market value of
the vested portion of such options in an amount determined using the
Black-Scholes method. The deferred compensation expense associated with the
unvested portion of the grants was determined to be approximately $1,338,000. As
part of the revision of the options, Drs. Weissman and Gage relinquished all
rights under an agreement. These individuals had the right to license the
non-brain stem cell technology in exchange for a payment to the Company equal to
all prior funding for such research plus royalty payments. We plan to revalue
the options using the Black-Scholes method on a quarterly basis and recognize
additional compensation expense accordingly.

                                      F-15

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

5.  INVESTMENTS

    In October 1997, the Company completed a series of transactions, which
resulted in the establishment of its previously 50%-owned Swiss subsidiary,
Modex Therapeutics, Ltd., (Modex) as an independent company.

    In April 1998, Modex completed an additional equity offering, in which the
Company did not participate. This resulted in a reduction in the Company's
ownership to less than 20% ownership; therefore, the Company accounted for this
investment under the cost method from that date.

    At December 31, 2000 the Company owned 126,193 shares of Modex. Modex
completed an initial public offering of shares on the Swiss Exchange on
June 23, 2000. Accordingly, with an established market value, the investment is
recorded as available-for-sale at a fair market value of $16,356,334 as at
December 31, 2000. The unrealized gain was reported as other comprehensive
income in the statement of stockholders' equity.

    The pre-existing royalty-bearing Cross License Agreement between the Company
and Modex was assigned by the Company to Neurotech S.A., a privately held French
company, as part of the sale of the intellectual property assets related to the
Company's encapsulated cell therapy technology to Neurotech. Under the terms of
the sale to Neurotech, the Company will receive a portion of revenues Neurotech
receives from Modex under the Cross License Agreement.

6.  PROPERTY, PLANT AND EQUIPMENT

    Property, plant and equipment consists of the following:



                                                            DECEMBER 31,
                                                       -----------------------
                                                          2000         1999
                                                       ----------   ----------
                                                              
Building and improvements............................  $  703,095   $  665,890
Machinery and equipment..............................   1,766,448    1,691,136
Furniture and fixtures...............................     188,736      219,260
                                                       ----------   ----------
                                                        2,658,279    2,576,286
Less accumulated depreciation and amortization.......  (1,207,218)    (828,401)
                                                       ----------   ----------
                                                       $1,451,061   $1,747,885
                                                       ==========   ==========


    Depreciation expense was $451,000, $1,436,000, and $1,720,000 for the years
ending December 31, 2000, 1999 and 1998, respectively.

    As part of restructuring our operations, sale of our encapsulated cell
technology ("ECT"), and relocation of our corporate headquarters to Sunnyvale,
California, we identified fixed assets associated with the ECT or otherwise no
longer needed. In December of 1999, we disposed of these excess fixed assets,
realizing proceeds of approximately $746,000. These assets had a net book value
of approximately $1,063,000 after a write-down of 800,000, which was based on an
estimate of expected sale proceeds.

    Certain property, plant and equipment have been acquired under capital lease
obligations. These assets totaled $5,827,000 at December 31, 2000 and 1999,
respectively, with related accumulated amortization of $2,747,000 at
December 31, 2000 and 1999, respectively. As a result of the Company's

                                      F-16

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

6.  PROPERTY, PLANT AND EQUIPMENT (CONTINUED)
decision to exit ECT and relocate to Sunnyvale, California, this property has
been classified as held for sale.

7.  OTHER ASSETS

    Other assets are as follows:



                                                            DECEMBER 31,
                                                       -----------------------
                                                          2000         1999
                                                       ----------   ----------
                                                              
Patents, net.........................................  $  629,203   $  708,823
License agreements, net..............................     669,000      282,750
Security deposit--building lease.....................     750,000      750,000
Deposit--other.......................................      16,321           --
Deferred financing costs, net........................     109,388      117,195
                                                       ----------   ----------
                                                       $2,173,912   $1,858,768
                                                       ==========   ==========


    At December 31, 2000 and 1999, accumulated amortization was $1,140,000 and
$857,000, respectively, for patents and license agreements.

8.  ACCRUED EXPENSES

    Accrued expenses are as follows:



                                                             DECEMBER 31,
                                                          -------------------
                                                            2000       1999
                                                          --------   --------
                                                               
External services.......................................  $219,051   $ 97,439
Employee compensation...................................   109,007    306,342
Collaborative research..................................        --    222,140
Other...................................................   509,300    344,625
                                                          --------   --------
                                                          $837,358   $970,546
                                                          ========   ========


9.  LEASES

    The Company has undertaken direct financing transactions with the State of
Rhode Island and received proceeds from the issuance of industrial revenue bonds
totaling $5,000,000 to finance the construction of its pilot manufacturing
facility. The related leases are structured such that lease payments will fully
fund all semiannual interest payments and annual principal payments through
maturity in August 2014. Fixed interest rates vary with the respective bonds'
maturities, ranging from 5.1% to 9.5%. The bonds contain certain restrictive
covenants which limit, among other things, the payment of cash dividends and the
sale of the related assets. In addition, the Company was required to maintain a
debt service reserve until December 1999. On March 3, 2000 the Company entered
into a settlement agreement with RIPSAT, the Rhode Island Industrial
Recreational Building Authority ("IRBA") and the Rhode Island Industrial
Facilities Corporation ("RIIFC"). The Company agreed to pay RIPSAT $1,172,000 in
full satisfaction of all obligations of the Company to RIPSAT under the

                                      F-17

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

9.  LEASES (CONTINUED)
Funding Agreement dated as of June 22, 1989. On execution and delivery of this
Agreement, IRBA agreed to return to the Company the full amount of the Company's
debt serve reserve ("Reserve Funds") of approximately $610,000 of principal and
interest, relating to the bonds the Company has with IRBA and RIIFC. In order to
avoid the loss of interest on the Reserve Funds due to early termination of
certain investments, the parties agreed that the Company would render a net
payment to RIPSAT in the amount of approximately $562,000.

    The Company entered into a fifteen-year lease for a laboratory facility in
connection with a sale and leaseback arrangement in 1997. The lease has a rent
escalation clause and accordingly, the Company is recognizing rent expense on a
straight line basis. At December 31, 2000, the Company has $705,746 in deferred
rent expense.

    As of February 1, 2001, the Company entered into a 5-year lease for a 40,000
square foot facility located in the Stanford Research Park in Palo Alto, CA. The
new facility includes vivarium space, laboratories, offices, and a GMP (Good
Manufacturing Practices) suite. GMP facilities can be used to manufacture
materials for clinical trials. The rent will average approximately
$3.15 million per year over the term of the lease.

    As of December 31, 2000, future minimum lease payments under operating and
capital leases and principal payments on equipment loans are as follows:



                                           CAPITAL      OPERATING     SUBLEASE
                                            LEASES       LEASES        INCOME
                                          ----------   -----------   ----------
                                                            
2001....................................  $  589,217   $ 3,584,061   $  295,854
2002....................................     519,719     2,392,988      400,658
2003....................................     436,909     4,568,274      395,676
2004....................................     425,713     4,677,197      416,507
2005....................................     412,587     4,789,388      437,338
Thereafter..............................   2,311,577     8,797,417      130,761
                                          ----------   -----------   ----------
Total minimum lease payments............   4,695,722   $28,809,325   $2,076,794
                                          ==========   ===========
Less amounts representing interest......   1,758,639
Present value of minimum lease
  payments..............................   2,937,083
Less current maturities.................     332,083
                                          ----------
Capitalized lease obligations, less
  current maturities....................  $2,605,000
                                          ==========


    Rent expense for the years ended December 31, 2000, 1999 and 1998, was
$1,111,000, $947,000 and $1,052,000, respectively.

10.  STOCKHOLDERS' EQUITY

SALE OF COMMON STOCK

    On August 3, 2000, the Company completed a $4 million common stock financing
transaction with Millennium Partners, LP (the "Fund"). StemCells received
$3 million of the purchase price at the

                                      F-18

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

10.  STOCKHOLDERS' EQUITY (CONTINUED)
closing and received the remaining $1 million upon effectiveness of a
registration statement covering the shares owned by the Fund. The Fund purchased
the Company's common stock and warrants at $4.33 per share. As set forth in an
adjustable warrant issued to the Fund on the closing date, the Fund may be
entitled to receive additional shares of common stock on eight dates beginning
six months from the closing and every three months thereafter. The adjustable
warrant may be exercised at any time prior to the thirtieth day after the last
of such dates. The number of additional shares the Fund may be entitled to on
each date will be based on the number of shares of common stock the Fund
continues to hold on each date and the market price of the Company's common
stock over a period prior to each date. The exercise price per share under the
adjustable warrant is $0.01. Such warrants provide the Fund with the opportunity
to acquire additional common shares at a nominal value if the value of the
common stock that the Fund holds decreases. The Company will have the right,
under certain circumstances, to cap the number of additional shares by
purchasing part of the entitlement from the Fund at a purchase price based on
the market price of such shares. No portion of the sale proceeds was assigned to
the adjustable warrants, as the ultimate number of shares issuable upon exercise
of the warrants was not determinable and the net impact on the Company's equity
from any such allocation of proceeds would have been zero. The Fund also
received a five-year warrant to purchase up to 101,587 shares of common stock at
$4.725 per share. This warrant is callable at any time by StemCells at
$7.875 per underlying share. The calculated value of this callable warrant using
the Black-Scholes method is $376,888, which was treated as a credit to paid in
capital in stockholders' equity. The Company accounts for the sale of the stock
and warrants or the exercise of warrants by adding that portion of the proceeds
equal to the par value of the new shares to common stock and the balance,
including the value of the warrants, to paid in capital. In addition, any
repurchase of the shares or warrants by the Company would also be accounted for
through paid in capital.

    In the Purchase Agreement governing the August 3, 2000 sale to the Fund, the
Company granted the Fund an option to purchase up to an additional $3 million of
its common stock and a callable warrant and an adjustable warrant. The Fund can
exercise this option in whole or in part at any time prior to August 3, 2001.
The price per share of common stock to be issued upon exercise of the option
will be based on the average market price of the common stock for a five-day
period prior to the date on which the option is exercised. On August 23, 2000,
the Fund exercised $1,000,000 of its option to purchase additional common stock.
The Fund paid $750,000 of the purchase price in connection with the closing on
August 30, 2000, and the Fund paid the remaining $250,000 upon effectiveness of
a registration statement covering the shares owned by the Fund. The Fund
purchased the Company's common stock at $5.53 per share, which amount was based
upon the average market price of the common stock for the five-day period prior
to August 23, 2000. An adjustable warrant similar to the one issued on
August 3, 2000 was issued to the Fund on August 30, 2000, but was cancelled on
November 1, 2000 by agreement of the Company and the Fund. The Fund also
received a five -year warrant to purchase up to 19,900 shares of common stock at
$6.03 per share. This warrant is callable by the Company at any time at
$10.05 per underlying share. The calculated value of this callable warrant using
the Black-Scholes method is $139,897, which the Company accounted for as a
credit to paid in capital.

    The adjustable warrant contains provisions regarding the adjustment or
replacement of the warrants in the event of stock splits, mergers, tender offers
and other similar events. The adjustable

                                      F-19

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

10.  STOCKHOLDERS' EQUITY (CONTINUED)
warrant also limits the number of shares that can be beneficially owned by the
Fund to 9.99% of the total number of outstanding shares of Common Stock.

REDEEMABLE COMMON STOCK

    In November 1996, the Company signed certain collaborative development and
licensing agreements with Genentech, Inc, including one under which Genentech
purchased 829,171 shares of redeemable common stock for $8.3 million to fund
development of products to treat Parkinson's disease. The Agreement also
provided that Genentech had the right, at its discretion, to terminate the
Parkinson's program at specified milestones in the program, and that if the
program were terminated, Genentech had the right to require the Company to
repurchase from Genentech the shares of the Company's common stock having a
value equal to the amount by which the $8.3 million exceeded the expenses
incurred by the Company in connection with such studies by more than
$1 million, based upon the share price paid by Genentech. Accordingly, the
common stock is classified as redeemable common stock until such time as the
related funds are expended. At December 31, 1998, $3,051,000 had been spent on
the collaboration with Genentech and, accordingly, the Company has reclassified
those common shares and related value to stockholders' equity. On May 21, 1998,
Genentech exercised its right to terminate the collaboration and negotiations
ensued with respect to the amount of redeemable common stock to be redeemed in
accordance with the agreement and the method of such redemption. In March 2000,
the Company reached a settlement of this matter with Genentech. Under the
settlement agreement, Genentech released the Company from any obligation to
redeem any shares of the Company's Common Stock held by Genentech. Accordingly,
the Company reclassified the amount currently recorded as Redeemable Common
Stock ($5,248,000) to Stockholders' Equity in March 2000. The Company and
Genentech also agreed that all of the agreements between them were terminated
and that neither had any claim to the intellectual property of the other.

STOCK ISSUED FOR TECHNOLOGY LICENSES

    Under a 1997 License Agreement with NeuroSpheres, Ltd., the Company obtained
an exclusive patent license in the field of transplantation. The Company entered
into an additional license agreement with NeuroSpheres as of October 31, 2000,
under which the Company obtained an exclusive license in the field of
non-transplant uses, such as drug discovery and drug testing, so that together
the licenses are exclusive for all uses of the technology. The Company made
up-front payments to NeuroSpheres of 65,000 shares of its common stock and
$50,000, and will make additional cash payments when milestones are achieved in
the non-transplant field, or in any products employing NeuroSpheres patents for
generating cells of the blood and immune system from neural stem cells.

    The Company also entered into license agreements with the California
Institute of Technology and issued 12,800 shares of common stock upon execution
of the license agreements. The Company must pay an additional $10,000 upon the
issuance of the patent licensed under the relevant agreement

COMMON STOCK ISSUED

    In 1998, the Company entered into an agreement with a Company advisor, under
which the advisor prepared a strategic and business overview and provided
related implementation support for the Company. The advisor agreed to accept
cash and the Company's common stock as partial payment for its services. In
1999, the Company issued the $187,500 of common stock due to the advisor.

                                      F-20

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

10.  STOCKHOLDERS' EQUITY (CONTINUED)

SALE OF 6% CUMULATIVE CONVERTIBLE PREFERRED STOCK

    On April 13, 2000 the Company issued 1,500 shares of 6% cumulative
convertible preferred stock plus a warrant for 75,000 shares of our common stock
to two members of its Board of Directors for $1.500,000 on terms more favorable
to the Company than it was then able to obtain from outside investors. The
shares are convertible at the option of the holders into common stock at $3.77
per share (based on the face value of the preferred shares). The conversion
price may be below the trading market price of the stock at the time of
conversion. The Company has valued the beneficial conversion feature reflecting
the April 13, 2000 commitment date and the most beneficial per share discount
available to the preferred shareholders. Such value was $481,000 and is treated
as a deemed dividend as of the commitment date. The holders of the preferred
stock have liquidation rights equal to their original investment plus accrued
but unpaid dividends.

STOCK OPTION AND EMPLOYEE STOCK PURCHASE PLANS

    The Company has adopted several stock plans that provide for the issuance of
incentive and nonqualified stock options, performance awards and stock
appreciation rights, at prices to be determined by the Board of Directors, as
well as the purchase of Common Stock under an employee stock purchase plan at a
discount to the market price. In the case of incentive stock options, such price
will not be less than the fair market value on the date of grant. Options
generally vest ratably over four years and are exercisable for ten years from
the date of grant or within three months of termination. At December 31, 2000,
the Company had reserved 3,828,371 shares of common stock for the exercise of
stock options.

    The following table presents the combined activity of the Company's stock
option plans (exclusive of the plans noted below) for the years ended
December 31:



                                            2000                         1999                         1998
                                 --------------------------   --------------------------   ---------------------------
                                                WEIGHTED                     WEIGHTED                      WEIGHTED
                                                AVERAGE                      AVERAGE                       AVERAGE
                                  OPTIONS    EXERCISE PRICE    OPTIONS    EXERCISE PRICE    OPTIONS     EXERCISE PRICE
                                 ---------   --------------   ---------   --------------   ----------   --------------
                                                                                      
Outstanding at January 1.......    939,335       $2.65        1,654,126        $3.62        2,446,573        $7.48
Granted........................  2,485,090        4.08          536,078         1.08        1,174,118         1.70
Exercised......................   (540,927)       1.015        (604,362)        1.50          (11,012)         .12
Canceled.......................   (166,532)       4.77         (646,507)        5.31       (1,955,553)        7.08
                                 ---------       ------       ---------        -----       ----------        -----
Outstanding at December 31.....  2,716,966        4.32          939,335        $2.65        1,654,126        $3.62
                                 =========       ======       =========        =====       ==========        =====
Options exercisable at
  December 31..................    731,523       $4.01          594,216        $3.44        1,108,936        $4.33
                                 =========       ======       =========        =====       ==========        =====


    In addition to the options noted above, in conjunction with the StemCells
California merger, StemCells California options originally issued under a prior
StemCells California options plan were exchanged for options to purchase 250,344
shares of the Company's common stock at $.01 per share; 96,750 of these options
vest and become exercisable only upon achievement of specified milestones, and
the remaining 78,210 options vest over three years from the date of grant.
Additionally, the Company adopted the 1997 StemCells, Inc. StemCells California
Research Stock Option Plan (the StemCells California Research Plan) whereby an
additional 2,000,000 shares of Common Stock have

                                      F-21

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

10.  STOCKHOLDERS' EQUITY (CONTINUED)
been reserved. During 1997, the Company awarded options under the StemCells
Research Plan to purchase 1.6 million shares of the Company's common stock to
the Chief Executive Officer and scientific founders of StemCells at an exercise
price of $5.25 per share; approximately 100,000 of these options were
exercisable immediately, 1,031,000 of these options vest and become exercisable
only upon achievement of specified milestones and the remaining 469,000 options
vest over eight years. For the year 2000 the options have been incorporated into
the number of options granted so as to be reflected in the total of options
outstanding as of December 31, 2000

FAS 123 DISCLOSURES

    The Company has adopted the disclosure provisions only of Statement of
Financial Accounting Standards No. 123, ACCOUNTING FOR STOCK-BASED COMPENSATION
("FAS 123") and accounts for its stock option plans in accordance with the
provisions of APB 25, ACCOUNTING FOR STOCK ISSUED TO EMPLOYEES.

    The following table presents weighted average price and life information
about significant option groups outstanding at December 31, 2000:



                                                    OPTIONS OUTSTANDING             OPTIONS EXERCISABLE
                                            ------------------------------------   ----------------------
                                                           WEIGHTED
                                                            AVERAGE     WEIGHTED                 WEIGHTED
                                                           REMAINING    AVERAGE                  AVERAGE
RANGE OF                                      NUMBER      CONTRACTUAL   EXERCISE     NUMBER      EXERCISE
EXERCISE PRICES                             OUTSTANDING   LIFE (YRS.)    PRICE     EXERCISABLE    PRICE
---------------                             -----------   -----------   --------   -----------   --------
                                                                                  
Less than $5.00...........................     944,216        8.68      $ 2.063      370,023      $ 1.53
$5.01 - $10.00............................   1,691,750        6.87        5.26       280,500        5.27
Greater than $10.00.......................      81,000        1.30       11.03        81,000       11.03
                                             ---------                               -------
                                             2,716,966                               731,523
                                             =========                               =======


    Pursuant to the requirements of FAS 123, the following are the pro forma net
loss and net loss per share amounts for 2000, 1999, and 1998, as if the
compensation cost for the option plans and the stock purchase plan had been
determined based on the fair value at the grant date for grants in 2000, 1999,
and 1998, consistent with the provisions of FAS 123:



                                  2000                          1999                          1998
                       ---------------------------   ---------------------------   ---------------------------
                       AS REPORTED     PRO FORMA     AS REPORTED     PRO FORMA     AS REPORTED     PRO FORMA
                       ------------   ------------   ------------   ------------   ------------   ------------
                                                                                
Net loss.............  $(11,125,477)  $(12,160,752)  $(15,708,626)  $(15,764,569)  $(12,627,830)  $(14,919,389)
Net loss per share...  $       (.58)  $       (.62)  $       (.84)  $       (.84)  $       (.69)  $       (.82)


    The weighted average fair value per share of options granted during 2000,
1999 and 1998 was $4.13, $.82 and $3.40, respectively. The fair value of options
and shares issued pursuant to the stock

                                      F-22

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

10.  STOCKHOLDERS' EQUITY (CONTINUED)
purchase plan at the date of grant were estimated using the Black-Scholes model
with the following weighted average assumptions:



                                                     OPTIONS                            STOCK PURCHASE PLAN
                                       ------------------------------------      ---------------------------------
                                         2000          1999          1998          2000       1999          1998
                                       --------      --------      --------      --------   --------      --------
                                                                                        
Expected life (years)................     5             5             5            N/A          .5            .5
Interest rate........................     6.5%          5.5%          5.2%         N/A         5.0%          4.6%
Volatility...........................   167.8          96.7%         63.5%         N/A        96.7%         63.5%


    The Company has never declared nor paid dividends on any of its capital
stock and does not expect to do so in the foreseeable future. On August 04, 1999
the board suspended the 1992 Employee Stock Purchase Plan.

    The effects on pro forma net loss and net loss per share of expensing the
estimated fair value of stock options and shares issued pursuant to the stock
purchase plan are not necessarily representative of the effects on reporting the
results of operations for future years. As required by FAS 123, the Company has
used the Black-Scholes model for option valuation, which method may not
accurately value the options described.

STOCK WARRANTS

    The Company issued warrants to purchase 8,952 shares of common stock in
conjunction with the StemCells California merger, warrants to purchase 31,545
shares in conjunction with various equipment leasing agreements, and warrants to
purchase 434,500 shares in connection with a public offering of common stock in
April 1995. All of these expired at various dates in 2000.

COMMON STOCK RESERVED

    The Company has the following shares of common stock reserved for the
exercise of options, warrants and other contingent issuances of common stock.


                                                           
Shares reserved for exercise of stock options...............  3,828,371
Shares reserved for warrants................................  2,292,625
StemCell option conversions.................................    250,344
                                                              ---------
Total.......................................................  6,371,340
                                                              =========


11.  RESEARCH AGREEMENTS

    In November 1997, StemCells California, Inc., a wholly owned subsidiary of
the Company, signed a Research Funding and Option Agreement with The Scripps
Research Institute ("Scripps") relating to certain stem cell research. Under the
terms of the Agreement, StemCells agreed to fund research in the total amount of
approximately $931,000 at Scripps over a period of three years. StemCells paid
Scripps approximately $307,000 in 1998, $309,000 in 1999, and $225,739 in 2000.
In addition, the Company agreed to issue to Scripps 4,837 shares of the
Company's common stock and a stock option to purchase 9,674 shares of the
Company's Common Stock with an exercise price of $.01 per share

                                      F-23

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

11.  RESEARCH AGREEMENTS (CONTINUED)
upon the achievement of specified milestones. Under the Agreement, StemCells has
an option for an exclusive license to the inventions resulting from the
sponsored research, subject to the payment of royalties and certain other
amounts, and is obligated to make payments totaling $425,000 for achievement of
certain milestones.

    In March 1995, the Company signed a collaborative research and development
agreement with AstraZeneca for the development and marketing of certain
encapsulated-cell products to treat pain. AstraZeneca made an initial,
nonrefundable payment of $5,000,000, included in revenue from collaborative
agreements in 1995, a milestone payment of $3,000,000 in 1997 and was to remit
up to an additional $13,000,000 subject to achievement of certain development
milestones. Under the agreement, the Company was obligated to conduct certain
research and development pursuant to a four-year research plan agreed upon by
the parties. Over the term of the research plan, the Company originally expected
to receive annual payments of $5 million to $7 million from AstraZeneca, which
was to approximate the research and development costs incurred by the Company
under the plan. Subject to the successful development of such products and
obtaining necessary regulatory approvals, AstraZeneca was obligated to conduct
all clinical trials of products arising from the collaboration and to seek
approval for their sale and use. AstraZeneca had the exclusive worldwide right
to market products covered by the agreement. Until the later of either the
expiration of all patents included in the licensed technology or a specified
fixed term, the Company was entitled to a royalty on the worldwide net sales of
such products in return for the marketing license granted to AstraZeneca and the
Company's obligation to manufacture and supply products. AstraZeneca had the
right to terminate the original agreement beginning April 1, 1998. On June 24,
1999, AstraZeneca informed the Company of the results of AstraZeneca's analysis
of the double-blind, placebo-controlled trial of the Company's encapsulated
bovine cell implant for the treatment of severe, chronic pain in cancer
patients. AstraZeneca determined that, based on criteria it established, the
results from the 85-patient trial did not meet the minimum statistical
significance for efficacy established as a basis for continuing worldwide trials
for the therapy. AstraZeneca therefore indicated that it did not intend to
continue the trials of the bovine cell-containing implant therapy and executed
its right to terminate the agreement. The Company has no additional funding
obligations with AstraZeneca.

    The Company has entered into other collaborative research agreements whereby
the Company funds specific research programs. Pursuant to such agreements, the
Company is typically granted rights to the related intellectual property or an
option to obtain such rights on terms to be agreed, in exchange for research
funding and specified royalties on any resulting product revenue. The Company's
principal academic collaborations had been with Brown University and
Dr. Aebischer and Centre Hospitalier Universitaire Vaudois in Switzerland.
However, with the termination of the Company's encapsulated cell technology
program and its new focus on the stem cell field, its principal academic
collaborations are now with Scripps Institute and the Oregon Health Science
University. Research and development expenses incurred under these
collaborations amounted to approximately $314,000, $868,000, and $1,259,000 for
the years ended December 31, 2000, 1999 and 1998, respectively. The Company has
no other significant collaborative research funding obligations.

                                      F-24

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

12.  INCOME TAXES

    Due to net losses incurred by the Company in each year since inception, no
provision for income taxes has been recorded. At December 31, 2000, the Company
had tax net operating loss carry forwards of $110,000,000 and research and
development tax credit carry forwards of $4,100,000, which expire in the years
2004 through 2020. Utilization of the Company's net operating loss may be
subject to substantial annual limitation due to the ownership change limitations
provided by the Internal Revenue Code and similar state provisions. Such an
annual limitation could result in the expiration of the net operating loss
before utilization.

    Significant components of the Company's deferred tax assets and liabilities
are as follows:



                                                          DECEMBER 31,
                                                   ---------------------------
                                                       2000           1999
                                                   ------------   ------------
                                                            
Deferred tax assets:
  Capitalized research and development costs.....  $  6,000,000   $  4,331,000
  Net operating losses...........................    44,000,000     38,478,000
  Research and development credits...............     4,260,000      4,035,000
  Other..........................................     1,020,000        928,000
                                                   ------------   ------------
                                                     55,280,000     47,772,000

Deferred tax liabilities:
  Unrealized gain on investment..................    (6,543,000)            --
  Patents........................................      (127,000)      (246,000)
  Valuation allowance............................   (48,610,000)   (47,526,000)
                                                   ------------   ------------
Net deferred tax assets..........................  $         --   $         --
                                                   ============   ============


    Realization of deferred tax assets is dependent upon future earnings, if
any, the timing and amount of which are uncertain. Accordingly, the net deferred
tax assets have been fully offset by a valuation allowance. The valuation
allowance increased by $6,272,000 during 1999, and $5,459,000 during 1998.

13.  EMPLOYEE RETIREMENT PLAN

    The Company has a qualified defined contribution plan covering substantially
all employees. Participants are allowed to contribute a fixed percentage of
their annual compensation to the plan and the Company may match a percentage of
that contribution. The Company matches 50% of employee contributions, up to 6%
of employee compensation, with the Company's common stock. The related expense
was $33,000, $103,000, and $146,000 for the years ended December 31, 2000, 1999
and 1998, respectively.

14.  SUBSEQUENT EVENTS (UNAUDITED)

    As of February 1, 2001, the Company entered into a 5-year lease for a 40,000
square foot facility located in the Stanford Research Park in Palo Alto,
California. The new facility includes animal space, laboratories, offices, and a
GMP (Good Manufacturing Practices) suite. GMP facilities can be used to
manufacture materials for clinical trials. The rent will average approximately
$3.15 million per year over the term of the lease. The Company continues to
lease the facilities in Lincoln, Rhode Island

                                      F-25

                                STEMCELLS, INC.

             NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

                               DECEMBER 31, 2000

14.  SUBSEQUENT EVENTS (UNAUDITED) (CONTINUED)
obtained in connection with its former encapsulated cell technology, but has now
succeeded in subleasing parts of those facilities: the 3,000 square-foot cell
processing facility and approximately one-third of its former scientific and
administrative facility ("SAF"). The Company continues to seek to sublet the
remainder of the approximately 65,000 square foot SAF and the 21,000 square-foot
pilot manufacturing facility, or to assign or sell its interests in these
properties. There can be no assurance however, that we will be able to dispose
of these properties in a reasonable time, if at all.

    In February 2001, the Company was awarded a two-year, $300,000 per year
grant from the NIH's Small Business Innovation Research (SBIR) office. The
grant, which will support joint work with virologist Dr. Jeffrey Glenn at
Stanford University, is aimed at characterizing the human cells that can be
infected by human hepatitis viruses and to develop a small animal model using
the cells that are most infectable by these viruses to develop screening assays
and identify novel drug for the disease.

    On January 9, 2001, the Company sold 22,616 Modex shares for a net price of
182.00 Swiss francs per share, which converts to $112.76 per share, for total
proceeds of $2,550,000. In connection with this sale, the Company agreed not to
resell any more of its Modex shares until April 12, 2001. On March 07, 2001 the
market price of Modex stock was 145.00 Swiss francs which converts to $84.31
using exchange rates on that date, which represents an estimated fair market
value of $8,732,797 for the remaining shares. If the Company were to seek to
liquidate all or part of the remaining 103,577 Modex shares, the proceeds would
depend on the share price and foreign currency exchange rates at the time of
conversion.

15.  QUARTERLY FINANCIAL INFORMATION (UNAUDITED)



                                                            QUARTER
                                           -----------------------------------------
                                            FIRST      SECOND     THIRD      FOURTH
                                           --------   --------   --------   --------
                                             (IN THOUSANDS, EXCEPT PER SHARE DATA)
                                                                
2000:
  Net revenue............................  $    --    $    --    $    --    $    74
  Operating expenses.....................    1,799      1,939      2,553      6,378
  Net Loss...............................   (1,794)      (532)    (2,539)    (6,260)
  Basic and diluted net loss per share
    applicable to common shareholders
    before cumulative effect.............  $ (0.09)   $ (0.04)   $ (0.13)   $ (0.30)
  Cumulative effect of a change in
    accounting principle(1)..............       --         --         --    $ (0.01)
  Net loss per share applicable to common
    shareholders.........................  $ (0.09)   $ (0.04)   $ (0.13)   $ (0.31)
1999:
  Net revenue............................  $ 2,501    $ 2,521    $    --    $    --
  Operating expenses.....................    4,562      4,454      6,690      5,253
  Net Loss...............................   (1,932)    (1,840)    (6,711)    (5,226)
  Basic and diluted net loss per share...  $ (0.10)   $ (0.10)   $ (0.36)   $ (0.27)


                                      F-26

                                STEMCELLS, INC.

                     CONDENSED CONSOLIDATED BALANCE SHEETS



                                                              MARCH 31, 2001
                                                              --------------
                                                               (UNAUDITED)
                                                           
ASSETS
Current assets:
  Cash and cash equivalents.................................  $   4,499,158
  Short-term restricted investments.........................      8,412,650
  Accrued interest receivable...............................          9,706
  Prepaid rent..............................................        909,415
  Other current assets......................................        473,696
                                                              -------------
      Total current assets..................................     14,304,625
  Property held for sale....................................      3,203,491
  Property, plant and equipment, net........................      1,442,089
  Other assets net..........................................      2,556,457
                                                              -------------
Total assets................................................  $  21,506,661
                                                              =============
LIABILITIES AND STOCKHOLDERS' EQUITY
Current liabilities:
  Accounts payable..........................................  $     237,856
  Accrued expenses..........................................        785,064
  Accrued wind-down costs...................................      1,380,947
  Current maturities of capitalized lease obligations.......        333,333
                                                              -------------
Total current liabilities...................................      2,737,200
Capitalized lease obligations, less current maturities......      2,521,250
Deposits....................................................         26,000
Deferred rent...............................................        760,508
Stockholders' equity
  Convertible preferred stock, $.01 par value; 1,000,000
    shares authorized, 2,626 designated as 6% Cumulative
    Convertible Preferred Stock 1,500 shares issued and
    outstanding at March 31, 2000...........................      1,500,000
  Common stock, $.01 par value; 45,000,000 shares
    authorized; 21,458,211 shares issued and outstanding at
    March 31, 2001..........................................        214,612
  Additional paid in capital................................    137,608,696
  Accumulated deficit.......................................   (130,229,646)
  Accumulated other comprehensive income....................      8,412,650
  Deferred compensation.....................................     (2,044,609)
                                                              -------------
      Total stockholders' equity............................     15,461,703
                                                              -------------
      Total liabilities and stockholders' equity............  $  21,506,661
                                                              =============


     SEE ACCOMPANYING NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

                                      F-27

                                STEMCELLS, INC.

                CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

                                  (UNAUDITED)



                                                                 THREE MONTHS ENDED
                                                                      MARCH 31,
                                                              -------------------------
                                                                 2001          2000
                                                              -----------   -----------
                                                                      
Revenue from grants.........................................  $   100,000   $        --
Operating expenses:
  Research and development..................................    1,644,257       906,632
  General and administrative................................      996,862       657,714
  Wind-down expenses........................................           --       234,386
                                                              -----------   -----------
                                                                2,641,119     1,798,732
                                                              -----------   -----------

Loss from operations........................................   (2,541,119)   (1,798,732)

Other income (expense):
  Investment income.........................................       79,041        73,332
  Interest expense..........................................           --       (68,858)
  Gain on sale of investments...............................    2,550,230            --
  Other income..............................................      180,389            --
                                                              -----------   -----------
Total other income, net.....................................    2,809,660         4,474
                                                              -----------   -----------
Net income (loss)...........................................  $   268,541   $(1,794,258)
                                                              ===========   ===========

Basic Earnings Per Share
  Net income (loss) per share...............................  $      0.01   $     (0.09)
  Shares - basic net income (loss) per share................   20,989,127    19,329,517
Diluted Earnings Per Share
  Net income (loss) per share...............................  $      0.01   $     (0.09)
  Shares - diluted income per share.........................   22,405,358    19,329,517


     SEE ACCOMPANYING NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS.

                                      F-28

                                STEMCELLS, INC.

                       CONDENSED STATEMENTS OF CASH FLOWS

                                  (UNAUDITED)



                                                                 THREE MONTHS ENDED
                                                                      MARCH 31,
                                                              -------------------------
                                                                 2001          2000
                                                              -----------   -----------
                                                                      
Cash flows from operating activities:
  Net income (loss).........................................  $   268,541   ($1,794,258)
  Adjustments to reconcile net income (loss) to net cash
    used for operating activities:
    Depreciation and amortization...........................      142,554       204,449
    Gain on sale of investments.............................   (2,550,230)           --
    Compensation expense relating to the grant of stock
      options...............................................      128,220        43,750
    Net changes in operating assets and liabilities.........   (1,812,084)   (1,776,812)
                                                              -----------   -----------
  Net cash used in operating activities.....................   (3,822,999)   (3,322,870)
                                                              -----------   -----------

Cash flows from investing activities:
  Proceeds from sale of investments.........................    2,550,230            --
  Purchase of property, plant and equipment.................     (114,734)       (7,542)
  Acquisition of other assets...............................     (126,391)           --
  Proceeds from sales of technology.........................           --     2,800,000
                                                              -----------   -----------
  Net cash provided by investing activities.................    2,309,105     2,792,458
                                                              -----------   -----------

Cash flows from financing activities:
  Proceeds from the exercise of stock options and
    warrants................................................       26,605       352,557
  Principal payments under capitalized lease obligations....      (82,500)      (80,000)
                                                              -----------   -----------
  Net cash provided by (used by) financing activities.......      (55,895)      272,557
                                                              -----------   -----------
Net decrease in cash and cash equivalents...................   (1,569,789)     (257,855)
Cash and cash equivalents, beginning of period..............    6,068,947     4,760,064
                                                              -----------   -----------
Cash and cash equivalents, end of period....................  $ 4,499,158   $ 4,502,209
                                                              ===========   ===========

Supplemental disclosure of cash flow information:
  Interest paid.............................................  $    64,460   $    68,858


           SEE ACCOMPANYING NOTES TO CONDENSED FINANCIAL STATEMENTS.

                                      F-29

        NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)

                            MARCH 31, 2001 AND 2000

NOTE 1.  BASIS OF PRESENTATION

    On May 23, 2000, the company's name was changed to Stem Cells, Inc. from
CytoTherapeutics, Inc. by vote of the shareholders at the Annual Meeting. The
accompanying, unaudited, condensed consolidated financial statements have been
prepared by the Company in accordance with generally accepted accounting
principles for interim financial information and with the instructions to Form
10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of
the information and footnotes required by generally accepted accounting
principles for complete financial statements. In the opinion of management, the
accompanying financial statements include all adjustments, consisting of normal
recurring accruals, considered necessary for a fair presentation of the
financial position, results of operations and cash flows for the periods
presented. Results of operations for the three months ended March 31, 2001 are
not necessarily indicative of the results that may be expected for the entire
fiscal year ending December 31, 2001.

    The balance sheet at December 31, 2000 has been derived from the audited
financial statements at that date but does not include all of the information
and footnotes required for complete financial statements in accordance with
accounting principles generally accepted in the United States. For the complete
financial statements, refer to the audited financial statements and footnotes
thereto as of December 31, 2000, included on form 10-K as amended.

NOTE 2.  NET INCOME (LOSS) PER SHARE

    Basic net income (loss) per common share is computed using the weighted
average number of common shares outstanding during the period. Diluted net
income per share is computed using the weighted average of common and diluted
equivalent stock options and warrants outstanding during the period. We excluded
all stock options and warrants from the calculation of diluted loss per common
share for the period ended March 31, 2000, because these securities are
antidilutive during that period.

NOTE 3.  COMPREHENSIVE LOSS

    The only component of other comprehensive loss is unrealized gains and
losses on available for sale securities. For the three months ended March 31,
2001 and 2000, total comprehensive loss was $7,675,143 and $1,794,258
respectively.

NOTE 4.  WIND-DOWN OF ENCAPSULATED CELL TECHNOLOGY RESEARCH AND DEVELOPMENT
         PROGRAM

    As previously reported, in 1999 the Company restructured its operations to
abandon all further encapsulated cell technology research and concentrate its
resources on the research and development of its proprietary platform of stem
cell technologies. The Company relocated its remaining research and development
activities and its corporate headquarters to California, and has been seeking to
dispose of its former science and administrative and pilot manufacturing
facilities in Rhode Island. In December 2000, the company had a reserve of
$1,780,000 related to the carrying costs for the Rhode Island facilities through
2001. On February 2001, the Company subleased portions of the facilities and are
actively seeking to sublease, assign or sell our remaining interests in the
properties. However, there can be no assurance that the Company will be able to
dispose of these facilities in a reasonable time, if at all. At March 31,2001
the reserve was $1,381,000.



    RESERVE AS AT 12/31/2000       PAYMENTS        RESERVE AS AT 03/31/01
    ------------------------       --------        ----------------------
                                        
           $1,780,579              $399,632              $1,380,947


                                      F-30

  NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)

                            MARCH 31, 2001 AND 2000

NOTE 5.  INVESTMENTS

    At March 31, 2001, the Company owned 103,577 shares of Modex Therapeutics
Ltd. ("Modex"), a Swiss biotechnology company traded on the Swiss Exchange. On
January 9, 2001, the Company sold 22,616 Modex shares for a net price of 182.00
Swiss francs per share, which converts to $112.76 per share, for total proceeds
of $2,550,000. In connection with this sale, the Company agreed not to resell
any more of its Modex shares until April 12, 2001. Accordingly, with an
established market value, the investment is recorded as available-for-sale at an
estimated fair market value. On March 31, 2001 the market price of Modex stock
was 141.00 Swiss francs, or $81.22 using exchange rates on that date, which
represented an estimated fair market value of $8,412,650 for the remaining
shares. The unrealized gain was reported in other comprehensive income. The
Company liquidated the remaining 103,577 Modex shares on April 30, 2001 for
$5,232,168 net of commissions and other fees. See note 9.

NOTE 6.  SALE OF SECURITIES

    On August 3, 2000, the Company completed a $4 million common stock financing
transaction with Millennium Partners, LP (the "Fund"). The Fund purchased the
Company's common stock at $4.33 per share. As set forth in an adjustable warrant
issued to the Fund on the closing date, the Fund may be entitled to receive
additional shares of common stock on eight dates beginning six months from the
closing and every three months thereafter. The adjustable warrant may be
exercised at any time prior to the thirtieth day after the last of such dates.
On the first adjustment date, January 27, 2001, the Fund became entitled to
463,369 additional shares, and it has exercised its warrant as to such shares.
The number of additional shares the Fund may be entitled to on each date will be
based on the number of shares of common stock the Fund continues to hold on each
date and the market price of the Company's common stock over a period prior to
each date. The exercise price per share under the adjustable warrant is $.01.
The Company will have the right, under certain circumstances, to cap the number
of additional shares by purchasing part of the entitlement from the Fund at a
purchase price based on the market price of such shares. The Fund also received
a five-year warrant to purchase up to 101,587 shares of common stock at $4.725
per share. This warrant is callable at any time by StemCells at $7.875 per
underlying share. The calculated value of this callable warrant using the
Black-Scholes method is $376,888, which the Company accounts for as stock
issuance cost that has no impact on stockholders' equity. The Company has
accounted for the sale of the stock and warrants by adding that portion of the
proceeds equal to the par value of the new shares to common stock and the
balance, including the value of the warrants, to additional paid in capital. In
addition, any repurchase of the shares by the Company would also be accounted
for through additional paid in capital.

    In the Purchase Agreement governing the August 3, 2000 sale to the Fund, the
Company granted the Fund an option to purchase up to an additional $3 million of
its common stock and a callable warrant and an adjustable warrant. The Fund can
exercise this option in whole or in part at any time prior to August 3, 2001.
The price per share of common stock to be issued upon exercise of the option
will be based on the average market price of the common stock for a five-day
period prior to the date on which the option is exercised. On August 23, 2000,
the Fund exercised $1,000,000 of its option to purchase additional common stock.
The Fund purchased the Company's common stock at $5.53 per share, which amount
was based upon the average market price of the common stock for the five-day
period prior to August 23, 2000. An adjustable warrant similar to the one issued
on August 3, 2000 was issued to the Fund on August 30, 2000, but was cancelled
on November 1, 2000 by agreement of the Company and the Fund. The Fund also
received a five -year warrant to purchase up to 19,900 shares of common stock at
$6.03 per share. This warrant is callable by the Company at any time at $10.05
per

                                      F-31

  NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)

                            MARCH 31, 2001 AND 2000

NOTE 6.  SALE OF SECURITIES (CONTINUED)
underlying share. The calculated value of this callable warrant using the
Black-Scholes method is $139,897, which the Company accounts for as stock
issuance cost that has no impact on stockholders' equity.

    The adjustable warrant contains provisions regarding the adjustment or
replacement of the warrants in the event of stock splits, mergers, tender offers
and other similar events. The adjustable warrant also limits the number of
shares that can be beneficially owned by the Fund to 9.99% of the total number
of outstanding shares of Common Stock.

NOTE 7.  LEASES

    As of February 1, 2001, the Company entered into a 5-year lease for a 40,000
square foot facility located in the Stanford Research Park in Palo Alto,
California. The new facility includes animal space, laboratories, offices, and a
GMP (Good Manufacturing Practices) suite. GMP facilities can be used to
manufacture materials for clinical trials. The rent will average approximately
$3.2 million per year over the term of the lease. The company paid $1.2 million
upfront related to this new lease. Approximately $909,000 of this payment has
been recorded as prepaid rent and is being amortized over seven months. The
Company continues to lease the facilities in Lincoln, Rhode Island obtained in
connection with its former encapsulated cell technology, but has now succeeded
in subleasing parts of those facilities: the 3,000 square-foot cell processing
facility and approximately one-third of its former scientific and administrative
facility ("SAF"). The Company continues to seek to sublet the remainder of the
approximately 65,000 square foot SAF and the 21,000 square-foot pilot
manufacturing facility, or to assign or sell its interests in these properties.
There can be no assurance however, that we will be able to dispose of these
properties in a reasonable time, if at all.

NOTE 8.  GRANT

    In February 2001, the Company was awarded a two-year, $300,000 per year
grant from the NIH's Small Business Innovation Research (SBIR) office. The
grant, which will support joint work with virologist Dr. Jeffrey Glenn at
Stanford University, is aimed at characterizing the human cells that can be
infected by human hepatitis viruses and to develop a small animal model using
the cells that are most infectable by these viruses to develop screening assays
and identify novel drug for the disease. The company received and recognized as
revenue $100,000 from a prior SBIR grant relating to the neural program.

NOTE 9.  SUBSEQUENT EVENTS

    On April 30, 2001, StemCells sold its remaining 103,577 shares of Modex
Therapeutics at 87.3 Swiss francs per share, or $50.51 per share at the exchange
rate on that date, for total proceeds of $5,232,168 net of commissions and other
fees. In addition, on April 30, 2001, in consideration for $300,000 received
from Modex and the assistance of Modex in executing the sale of StemCells
holding of Modex shares, StemCells agreed to assign to Modex the rights
concerning future payments under the Asset Purchase and License Agreement
between StemCells, Inc. and Neurotech SA, by which Neurotech SA purchased the
Company's former encapsulated cell therapy technology.

                                      F-32

  NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED) (CONTINUED)

                            MARCH 31, 2001 AND 2000

NOTE 9.  SUBSEQUENT EVENTS (CONTINUED)
    On April 27, 2001, the Company reached an agreement to terminate as of May
15, 2001, without cost, its lease on part of its former Sunnyvale headquarters.

NOTE 10.  RECENT ACCOUNTING PRONOUNCEMENT

    In June 1998, The Financial Accounting Standards Board issued Statement of
Financial Accounting Standards No. 133, "Accounting for Derivative Financial
Instruments and for Hedging Activities" ("SFAS 133"). The Statement requires the
Company to recognize all derivatives on the balance sheet at fair value.
Derivatives that are not hedges must be adjusted to fair value through income.
If the derivative is a hedge, depending on the nature of the hedge, changes in
fair value of derivatives are either offset against the change in fair value of
assets, liabilities, or firm commitments through earnings or recognized in other
comprehensive income until the hedged item is recognized in earnings. As the
Company had no derivative instruments and does not currently engage in hedging
activities, the adoption of Statement No. 133 on January 1, 2001 had no impact
on StemCells results, operations or financial statement.

                                      F-33

                                    PART II
                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 13. OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

    The following table sets forth the costs and expenses payable by the
Registrant in connection with the sale of the securities being registered. All
amounts shown are estimates except the SEC registration fee.


                                                           
SEC registration fee........................................  $ 2,031
Printing and engraving expenses.............................  $ 5,000
Legal fees and expenses.....................................  $10,000
Accounting fees and expenses................................  $ 3,000
Miscellaneous...............................................  $10,000
                                                              -------
Total.......................................................  $30,031
                                                              =======


ITEM 14. INDEMNIFICATION OF DIRECTORS AND OFFICERS.

    Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify any person who was or is a party or is threatened to
be made a party to any threatened, pending or completed action, suit or
proceeding, whether civil, criminal, administrative or investigative, other than
an action by or in the right of the corporation, by reason of the fact that the
person is or was a director, officer, employee or agent of the corporation or is
or was serving at the corporation's request as a director, officer, employee or
agent of another corporation, partnership, joint venture, trust or other
enterprise, against expenses, including attorneys' fees, judgments, fines and
amounts paid in settlement actually and reasonably incurred by the person in
connection with the action, suit or proceeding if the person acted in good faith
and in a manner the person reasonably believed to be in or not opposed to the
best interests of the corporation, and, with respect to any criminal action or
proceeding, had no reasonable cause to believe the person's conduct was
unlawful. The power to indemnify applies to actions brought by or in the right
of the corporation as well, but only to the extent of expenses, including
attorneys' fees but excluding judgments, fines and amounts paid in settlement,
actually and reasonably incurred by the person in connection with the defense or
settlement of the action or suit and with the further limitation that in these
actions no indemnification shall be made in the event of any adjudication of
negligence or misconduct in the performance of his duties to the corporation,
unless a court believes that in light of all the circumstances indemnification
should apply.

    Section Ten of our Restated Certificate of Incorporation provides that we
shall, to the maximum extent legally permitted, indemnify and upon request
advance expenses to each person who is or was a party or is threatened to be
made a party to any threatened, pending or completed action, suit proceeding, or
claim (civil, criminal, administrative or investigative) by reason of the fact
that he is or was, or has agreed to become, a director or officer of the
Company, or is or was serving, or has agreed to serve, at the request of the
Company, as a director, officer, partner, employee, agent or trustee of, or in a
similar capacity with, another corporation, partnership, joint venture, trust or
other enterprises, provided, however, that the Company is not required to
indemnify or advance expenses to any person in connection with any action, suit,
proceeding, claim or counterclaim initiated by or on behalf of such person. The
indemnification provided for in Section Ten is expressly not exclusive of any
other rights to which those seeking indemnification may be entitled under any
by-law, agreement or vote of directors or stockholders or otherwise, and shall
inure to the benefit of the heirs and legal representatives of such persons.

    Section 145(g) of the Delaware General Corporation Law provides that the
Company shall have the power to purchase and maintain insurance on behalf of its
officers, directors, employees and agents, against any liability asserted
against and incurred by such persons in any such capacity.

                                      II-1

    We have obtained insurance covering our directors and officers against
certain liabilities.

    Section 102(b)(7) of the General Corporation Law of the State of Delaware
provides that a corporation may eliminate or limit the personal liability of a
director to the corporation or its stockholders for monetary damages for breach
of fiduciary duty as a director, provided that such provisions shall not
eliminate or limit the liability of a director (i) for any breach of the
director's duty of loyalty to the corporation or its stockholders, (ii) for acts
or omissions not in good faith or which involve intentional misconduct or a
knowing violation of law, (iii) under Section 174 of the General Corporation Law
of the State of Delaware, or (iv) for any transaction from which the director
derived an improper personal benefit. No such provision shall eliminate or limit
the liability of a director for any act or omission occurring prior to the date
when such provision becomes effective.

    Pursuant to the Delaware General Corporation Law, Section Nine of the
Company's Restated Certificate of Incorporation eliminates a director's personal
liability for monetary damages for breach of fiduciary duty as a director,
except in circumstances involving a breach of the director's duty of loyalty to
StemCells, Inc. or its shareholders, acts or omissions not in good faith,
intentional misconduct, knowing violations of the law, self-dealing or the
unlawful payment of dividends or repurchase of stock.

ITEM 15. RECENT SALES OF UNREGISTERED SECURITIES.

    The shares of capital stock and other securities issued in the following
transactions were offered and sold in reliance upon the following exemptions:
(i) in the case of the transactions described in (a), (b) and (d) below,
Section 4(2) of a the Securities Act or Regulation D promulgated thereunder
relative to sales by an issuer not involving a public offering; and (ii) in the
case of the transactions (c) below, Section 3(b) of the Securities Act and
Rule 701 promulgated thereunder relative to sales pursuant to certain
compensatory benefits plans.

    (a) On April 13, 2000, the Registrant sold 1,500 shares of 6% cumulative
convertible preferred stock plus warrants for a total of 75,000 shares of the
Registrant's common stock to two members of its Board of Directors for
$1,500,000, on terms more favorable than it was then able to obtain from outside
investors. The sale was made in reliance on Rule 506 of Regulation D promulgated
under the Securities Act of 1933, as amended. The shares of preferred stock are
convertible at the option of the holders into common stock at $3.77 per share
(based on the face value of the shares). The holders of the preferred stock have
liquidation rights equal to their original investments plus accrued but unpaid
dividends. Any unconverted preferred stock is converted, at the applicable
conversion price, on April 13, 2002. The warrants, which are exercisable at
$6.58 per share, expire on April 13, 2005.

    On August 3, 2000, the Registrant completed a $4 million common stock
financing transaction with Millennium Partners, LP, or the Fund. The sale was
made in reliance on Rule 506 of Regulation D promulgated under the Securities
Act of 1933, as amended. The Registrant received $3 million of the purchase
price at the closing and received the remaining $1 million upon effectiveness of
a registration statement covering the shares owned by the Fund. The Fund
purchased the Registrant's common stock at $4.33 per share. The Fund may be
entitled, pursuant to an adjustable warrant issued in connection with the sale
of common stock to the Fund, to receive additional shares of common stock on
eight dates beginning six months from the closing and every three months
thereafter. The number of additional shares the Fund may be entitled to on each
date will be based on the number of shares of common stock the Fund continues to
hold on each date and the market price of the Registrant's common stock over a
period prior to each date. The Registrant will have the right, under certain
circumstances, to cap the number of additional shares by purchasing part of the
entitlement from the Fund. On January 27, 2001, Millennium's August 3, 2000
adjustable warrant became exercisable for 463,369 shares of our common stock,
and Millennium purchased all of those shares for $4,634 on March 30, 2001. On
April 27, 2001, the adjustable warrant became exercisable for an additional
622,469 shares of our common stock, and Millennium purchased all of those shares
for $6,225 on July 19, 2001.

                                      II-2

The Fund also received a warrant to purchase up to 101,587 shares of common
stock at $4.725 per share. This warrant is callable by the Registrant at $7.875
per underlying share.

    The Fund also has the option for twelve months to purchase up to $3 million
of additional common stock. On August 23, 2000, the Fund exercised $1,000,000 of
that option to purchase Registrant's common stock at $5.53 per share. The
Registrant received $750,000 of the purchase price in connection with the
closing on August 30, 2000 and received the remaining $250,000 upon
effectiveness of a registration statement covering the shares owned by the Fund.
At the closing on August 30, 2000, the Fund also received an adjustable warrant
similar to the one issued on August 3, 2000. This adjustable warrant was
canceled by agreement of the Registrant and the Fund on November 1, 2000. The
Fund also received a five year warrant to purchase up to 19,900 shares of the
Registrant's common stock at $6.03 per share. This warrant is callable by the
Registrant at any time at $10.05 per underlying share.

    On June 8, 2001, the Fund exercised its remaining option to purchase
$2 million of additional common stock. At the closing on June 21, 2001, the Fund
purchased 457,750 shares of common stock at $4.3692 per share. The Fund paid
$1,500,000 of the purchase price at the closing and will pay the remainder upon
effectiveness of a registration statement covering the shares purchased by the
Fund and issuable upon exercise of the warrants received by the Fund. In
connection with the closing, the Fund received an adjustable warrant similar to
the adjustable warrant issued on August 3, 2000. The Fund also received a
five-year warrant to purchase 50,352 shares of additional common stock at a
price per share of $4.7664. This warrant is callable by the Registrant at any
time at $7.944 per underlying share.

    (b)  We entered into a license agreement with NeuroSpheres, Ltd. on
October 30, 2000 expanding our rights to the intellectual property covered by
the license agreement. See "Business--License Agreements and Sponsored Research
Agreements--Neurospheres, Ltd." Under that license agreement, on October 30,
2000, we issued 65,000 shares of our common stock to NeuroSpheres and we agreed
to file a registration statement covering the resale of those shares by
NeuroSpheres.

    (c)  On May 25, 2000 we issued 2,800 shares of unregistered Rule 144 common
stock to the California Institute of Technology.

    (d)  On May 10, 2001, we entered into a common stock purchase agreement with
Sativum Investments Limited, for the potential future issuance and sale of up to
$30,000,000 million of our common stock, subject to restrictions and other
obligations that are described throughout this prospectus. We, at our sole
discretion, may draw down on this facility, sometimes termed an equity line,
from time to time, and Sativum is obligated to purchase shares of our common
stock at a 6% discount to a volume weighted average market price over the 20
trading days following the drawdown notice. Our volume weighted average market
price is calculated by adding the total dollars traded in every transaction in a
given trading day and dividing that number by the total number of shares traded
during that trading day. We are limited with respect to how often we can
exercise a drawdown and the amount of each drawdown.

    The Registrant delivered a draw down notice to Sativum Investments Limited,
dated as of July 11, 2001, in connection with the common stock purchase
agreement dated as of May 10, 2001 evidencing an equity line facility between
the Registrant and Sativum. In the draw down notice, the Registrant notified
Sativum that it is exercising its right to sell up to $5,000,000 of its common
stock to Sativum based on the formula in the stock purchase agreement, during
the 20 trading days beginning on July 12, 2001, and ending on August 8, 2001.
During the first 10 trading days, Sativum purchased a total of 425,134 shares of
common stock at an average purchase price of $5.88 per share, net of Sativum's
discount of six percent. The Registrant's placement agents, Pacific Crest
Securities, Inc. and Granite Financial Group, Inc. received $50,000 and $25,000,
respectively, as placement fees in connection with this draw down, resulting in
net proceeds to the Registrant of $2,424,000 for the first 10 trading day
settlement period after paying escrow fees.

                                      II-3

ITEM 16. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES

    (a) EXHIBITS. The following exhibits are filed as part of this registration
       statement:



       NUMBER                                   DESCRIPTION
---------------------   ------------------------------------------------------------
                     
      3.1*              Restated Certificate of Incorporation of the Registrant

      3.2++             Amended and Restated By-Laws of the Registrant.

      4.1*              Specimen Common Stock Certificate.

      4.2++++           Form of Warrant Certificate issued to a certain purchaser of
                        the Registrant's Common Stock in April 1995.

      4.3X              Warrant to Purchase Common Stock--Mark Angelo.

      4.4X              Warrant to Purchase Common Stock--Robert Farrell.

      4.5X              Warrant to Purchase Common Stock--Joseph Donahue.

      4.6X              Warrant to Purchase Common Stock--Hunter Singer.

      4.7X              Warrant to Purchase Common Stock--May Davis.

      4.8X              Common Stock Purchase Warrant.

      4.9X              Callable Warrant, dated July 31, 2000, issued to Millennium
                        Partners, L.P.

      4.10XXX           Registration Rights Agreement dated as of May 10, 2001
                        between the Company and Sativum Investments Limited.

      4.11XXX           Warrant, dated May 10, 2001, to Purchase Common Stock issued
                        to Sativum Investments Limited.

      4.12XXX           Warrant, dated May 10, 2001, to Purchase Common Stock issued
                        to Pacific Crest Securities, Inc.

      4.13XXX           Warrant dated May 10, 2001, to Purchase Common Stock issued
                        to Granite Financial Group, Inc.

      4.14XXX           Callable Warrant, dated June 21, 2001, issued to Millennium
                        Partners, L.P.

      4.15XXX           Common Stock Purchase Warrant, Class A, dated June 21, 2001,
                        issued to Millennium Partners, L.P.

      5.1               Opinion of Ropes & Gray.

     10.1*              Amendment to Registration Rights dated as of February 14,
                        1992 among the Registrant and certain of its stockholders.

     10.2*              Form of at-will Employment Agreement between the Registrant
                        and most of its employees.

     10.3*              Form of Agreement for Consulting Services between the
                        Registrant and members of its Scientific Advisory Board.

     10.4*              Form of Nondisclosure Agreement between the Registrant and
                        its Contractors.

     10.5*              Master Lease and Warrant Agreement dated April 23, 1991
                        between the Registrant and PacifiCorp Credit, Inc.

     10.6*              1988 Stock Option Plan.

     10.7*              1992 Equity Incentive Plan.

     10.8*              1992 Stock Option Plan for Non-Employee Directors.

     10.9**!!!!         1992 Employee Stock Purchase Plan.


                                      II-4




       NUMBER                                   DESCRIPTION
---------------------   ------------------------------------------------------------
                     
     10.12++            Research Agreement dated as of March 16, 1994 between
                        NeuroSpheres, Ltd. and Registrant.

     10.13++            Term Loan Agreement dated as of September 30, 1994 between
                        The First National Bank of Boston and Registrant.

     10.14++            Lease Agreement between the Registrant and Rhode Island
                        Industrial Facilities Corporation, dated as of August 1,
                        1992.

     10.15++            First Amendment to Lease Agreement between Registrant and
                        The Rhode Island Industrial Facilities Corporation dated as
                        of September 15, 1994.

     10.17**++++        Development, Marketing and License Agreement, dated as of
                        March 30, 1995 between Registrant and Astra AB.

     10.18++++          Form of Unit Purchase Agreement to be executed by the
                        purchasers of the Common Stock and Warrants offered in April
                        1995.

     10.19+++           Form of Common Stock Purchase Agreement to be executed among
                        the Registrant and certain purchasers of the Registrant's
                        Common Stock.

     10.22###           Lease Agreement dated as of November 21, 1997 by and between
                        Hub RI Properties Trust, as Landlord, and CytoTherapeutics,
                        Inc., as Tenant.

     10.24!!            CTI individual stockholders option agreement dated as of
                        July 10, 1996 among the Company and the individuals listed
                        therein.

     10.25!!            CTI Valoria option agreement dated of July 10, 1996 between
                        the Company and the Societe Financiere Valoria SA.

     10.26!!!           Term Loan Agreement dated as of October 22, 1996 between The
                        First National Bank of Boston and the Registrant.

     10.27***           Agreement and Plan of Merger dated as of August 13, 1997
                        among StemCells, Inc., the Registrant and CTI Acquisition
                        Corp.

     10.28***           Consulting Agreement dated as of September 25, 1997 between
                        Dr. Irving Weissman and the Registrant.

     10.29###           Letter Agreement among each of Dr. Irving Weissman and Dr.
                        Fred H. Gage and the Registrant.

     10.32****          StemCells, Inc. 1996 Stock Option Plan.

     10.33****          1997 StemCells Research Stock Option Plan (the "1997 Plan").

     10.34****          Form of Performance-Based Incentive Option Agreement issued
                        under the 1997 Plan.

     10.35###           Employment Agreement dated as of September 25, 1997 between
                        Dr. Richard M. Rose and the Registrant.

     10.38[*]           Rights Agreement, dated as of July 27, 1998 between Bank
                        Boston, N.A. as Rights Agent and the Registrant.

     10.40Section**     Consulting Services Agreement dated as of July 27, 1998, as
                        amended December 19, 1998 between Dr. John J. Schwartz and
                        the Registrant.

     10.41Section**     Letter Agreement dated as of December 19, 1998 between John
                        J. Schwartz and the Registrant.

     10.42Section**     License Agreement dated as of October 27, 1998 between The
                        Scripps Research Institute and the Registrant.


                                      II-5




       NUMBER                                   DESCRIPTION
---------------------   ------------------------------------------------------------
                     
     10.43Section**     License Agreement dated as of October 27, 1998 between The
                        Scripps Research Institute and the Registrant.

     10.44Section**     License Agreement dated as of November 20, 1998 between The
                        Scripps Research Institute and the Registrant.

10.45SectionSection**   Purchase Agreement and License Agreement dated as of
                        December 29, 1999 between Neurotech S.A. and the Registrant.

     10.46**            License Agreement, dated as of June 1999, between The
                        Scripps Research Institute and the Registrant.

     10.47**            License Agreement, dated as of June 1999, between The
                        Scripps Research Institute and the Registrant.

     10.48X             Form of Registration Rights Agreement, dated as of July 31,
                        2000, between StemCells, Inc. and investors.

     10.49X             Subscription Agreement, dated as of July 31, 2000, between
                        StemCells, Inc. and Millennium Partners, L.P.

     10.50XXX           Common Stock Purchase Agreement, dated as of May 10, 2001,
                        between the Company and Sativum Investments Limited.

     10.51XXX           Esrow Agreement, dated as of May 10, 2001, among the
                        Company, Sativum Investments Limited and Epstein, Becker &
                        Green, P.C.

     10.52XX            License Agreement, dated as of October 30, 2000, between the
                        Company and Neuro Spheres Ltd.

     10.53XX            Letter Agreement, dated January 2, 2001, between the Company
                        and Martin McGlynn.

     10.54XX            Lease, dated February 1, 2001, between the Board of Trustees
                        of Stanford University and the Company.

     10.55XXX           Registration Rights Agreement, dated as of June 21, 2001, by
                        and between the Company and Millennium Partners, L.P.

     10.56XXX           Subscription Agreement, dated as of June 21, 2001, by and
                        between the Company and Millennium Partners, L.P.

10.57SectionSectionSection 2001 Equity Incentive Plan.

  21.1X                 Subsidiaries of the Registrant.

     23.1               Consent of Ernst & Young LLP, Independent Auditors.

     23.2               Consent of Ropes & Gray (included in the form of opinion
                        filed as Exhibit 5.1).

     24.1               Power of Attorney pursuant to which amendments to this
                        registration statement may be filed (contained on page II-9
                        hereto).

     99.2XX             Side Letter, dated March 17, 2001, between the Company and
                        Oleh S. Hnatiuk regarding NeuroSpheres License Agreement,
                        dated October 30, 2000.


------------------------

++   Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-1, File No. 333-85494.

+++  Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-3, File No. 333-97272.

++++ Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-1, File No. 333-91228.

                                      II-6

*      Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, Registration Statement on Form S-1, File
      No. 333-45739.

#     Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      fiscal year ended December 31, 1992 and filed March 30, 1993.

**     Confidential treatment requested as to certain portions. The term
      "confidential treatment" and the mark "**" as used throughout the
      indicated Exhibits mean that material has been omitted and separately
      filed with the Commission.

##   Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Quarterly Report on Form 10-Q for
      the quarter ended March 31, 1994 and filed on May 14, 1994.

+     Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 1993 and filed on March 30, 1994.

!      Previously filed with the Commission as an Exhibit to and incorporated by
      reference to, the Registrant's Quarterly Report on Form 10-Q for the
      quarter ended March 31, 1996.

!!     Previously filed with the Commission as an Exhibit to and incorporated by
      reference to, the Registrant's Quarterly Report on Form 10-Q for the
      quarter ended September 30, 1996.

!!!     Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 1996 and filed on March 31, 1997.

!!!!    Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 1995.

***    Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Quarterly Report on Form 10-Q for
      the quarter ended September 30, 1997 and filed on November 14, 1997.

****   Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-8, File No. 333-37313.

###  Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's annual report on Form 10-K for
      the fiscal year ended December 31, 1997 and filed on March 30, 1998.

[*]    Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's current report on Form 8-K filed
      on August 3, 1998.

Section      Previously filed with the Commission as an Exhibit to, and
      incorporated herein by reference to, the Registrant's annual report on
      Form 10-K for the fiscal year ended December 31, 1998 and filed on
      March 31, 1999.

SectionSection     Previously filed with the Commission as an Exhibit to, and
      incorporated herein by reference to, the Registrant's current report on
      Form 8-K on January 14, 2000.

SectionSectionSection    Previously filed with the Commission as an Exhibit to,
      and incorporated herein by reference to, the Registrant's definitive proxy
      statement filed May 1, 2001.

X     Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Registration Statement on Form
      S-1, File No. 333-45496.

XX   Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 2000 and filed on April 2, 2001.

XXX Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Registration Statement filed on
      Form S-1 as amended to Form S-3, File No. 333-61726.

                                      II-7

ITEM 17. UNDERTAKINGS.

    (a)  Insofar as indemnification for liabilities arising under the Securities
Act may be permitted to directors, officers and controlling persons of the
Registrant pursuant to the provisions described under Item 14 above, or
otherwise, the Registrant has been advised that in the opinion of the Securities
and Exchange Commission such indemnification is against public policy as
expressed in the Securities Act and is, therefore, unenforceable. In the event
that a claim for indemnification against such liabilities (other than the
payment by the Registrant of expenses incurred or paid by a director, officer or
controlling person of the Registrant in the successful defense of any action,
suit or proceeding) is asserted by such director, officer or controlling person
in connection with the securities being registered, the Registrant will, unless
in the opinion of its counsel the matter has been settled by controlling
precedent, submit to a court of appropriate jurisdiction the question whether
such indemnification by it is against public policy as expressed in the
Securities Act and will be governed by the final adjudication of such issue.

    (b) The undersigned Registrant hereby undertakes:

    (1) To file, during any period in which offers or sales are being made, a
       post-effective amendment to this registration statement:

        (i) To include any prospectus required by Section 10(a)(3) of the
            Securities Act of 1933;

        (ii) To reflect in the prospectus any facts or events arising after the
             effective date of the registration statement (or the most recent
             post-effective amendment thereof) which, individually or in the
             aggregate, represent a fundamental change in the information set
             forth in the registration statement. Notwithstanding the foregoing,
             any increase or decrease in volume of securities offered (if the
             total dollar value of securities offered would not exceed that
             which was registered) and any deviation from the low or high end of
             the estimated maximum offering range may be reflected in the form
             of prospectus filed with the Commission pursuant to Rule 424(b) if,
             in the aggregate, the changes in volume and price represent no more
             than 20 percent change in the maximum aggregate offering price set
             forth in the "Calculation of Registration Fee" table in the
             effective registration statement.

       (iii) To include any material information with respect to the plan of
             distribution not previously disclosed in the registration statement
             or any material change to such information in the registration
             statement.

    (2) For the purpose of determining any liability under the Securities Act,
       each post-effective amendment that contains a form of prospectus shall be
       deemed to be a new registration statement relating to the securities
       offered therein, and the offering of such securities at that time shall
       be deemed to be the initial BONA FIDE offering thereof.

    (3) To remove from registration by means of a post-effective amendment any
       of the securities being registered which remain unsold at the termination
       of the offering.

    (4) To file a post-effective amendment to the Registration Statement to
       include any financial statements required by section 10(a)(3) of the
       Securities Act.

    (c) The undersigned registrant hereby undertakes that, for purposes of
       determining any liability under the Securities Act of 1933, each filing
       of the registrant's annual report pursuant to Section 13(a) or 15(d) of
       the Securities Exchange Act of 1934 (and, where applicable, each filing
       of an employee benefit plan's annual report pursuant to Section 15(d) of
       the Securities Exchange Act of 1934) that is incorporated by reference in
       the registration statement shall be deemed to be a new registration
       statement relating to the securities offered therein, and the offering of
       such securities at that time shall be deemed to be the initial BONA FIDE
       offering thereof.

                                      II-8

                                   SIGNATURES

    Pursuant to the requirements of the Securities Act of 1933, the Registrant
has duly caused this Registration Statement to be signed on its behalf by the
undersigned, thereunto duly authorized, in the City of Palo Alto, State of
California, on the 3rd day of August, 2001.


                                                      
                                                       STEMCELLS, INC.

                                                       BY:  /S/ MARTIN M. MCGLYNN
                                                            -----------------------------------------
                                                            Martin M. McGlynn
                                                            Chief Executive Officer


                               POWER OF ATTORNEY

    Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities indicated on August 3, 2001. Each person whose signature appears
below hereby constitutes and appoints Martin M. McGlynn and Iris Brest, and
either of them, each with full power of substitution, his true and lawful
attorney-in-fact and agent with full power to him or her to sign for him and in
his name in the capacities indicated below any and all amendments (including
post-effective amendments) to this Registration Statement and to file the same,
with exhibits thereto, and other documents in connection therewith, and he
hereby ratifies and confirms his signature as it may be signed by said attorney
to any and all such amendments.



                      SIGNATURE                                            TITLE
                      ---------                                            -----
                                                    
                                                       Martin M. McGlynn,
                                                         President, Chief Executive Officer
                /s/ MARTIN M. MCGLYNN                    (Principal Executive Officer), Director
     -------------------------------------------

                                                       George Koshy,
                                                         Controller and Acting Chief Financial
                                                         Officer (Principal Financial Officer and
                  /s/ GEORGE KOSHY                       Principal Accounting Officer)
     -------------------------------------------

                                                       Mark J. Levin
                  /s/ MARK J. LEVIN                      Director
     -------------------------------------------

                                                       Roger M. Perlmutter, M.D., Ph.D.
               /s/ ROGER M. PERLMUTTER                   Director
     -------------------------------------------

                                                       John J. Schwartz, Ph. D.
                /s/ JOHN J. SCHWARTZ                     Director
     -------------------------------------------

                                                       Irving Weissman, M.D.
                                                         Director
     -------------------------------------------


                                      II-9

                                 EXHIBIT INDEX



       NUMBER                                   DESCRIPTION
---------------------   ------------------------------------------------------------
                     
      3.1*              Restated Certificate of Incorporation of the Registrant.

      3.2++             Amended and Restated By-Laws of the Registrant.

      4.1*              Specimen Common Stock Certificate.

      4.2++++           Form of Warrant Certificate issued to a certain purchaser of
                        the Registrant's Common Stock in April 1995.

      4.3X              Warrant to Purchase Common Stock--Mark Angelo.

      4.4X              Warrant to Purchase Common Stock--Robert Farrell.

      4.5X              Warrant to Purchase Common Stock--Joseph Donahue.

      4.6X              Warrant to Purchase Common Stock--Hunter Singer.

      4.7X              Warrant to Purchase Common Stock--May Davis.

      4.8X              Common Stock Purchase Warrant.

      4.9X              Callable Warrant, dated July 31, 2000, issued to Millennium
                        Partners, L.P.

      4.10XXX           Registration Rights Agreement, dated as of May 10, 2001,
                        between the Company and Sativum Investments Limited.

      4.11XXX           Stock Purchase Warrant, dated May 10, 2001, issued to
                        Sativum Investments Limited.

      4.12XXX           Stock Purchase Warrant, dated May 10, 2001, issued to
                        Pacific Crest Securities, Inc.

      4.13XXX           Stock Purchase Warrant, dated May 10, 2001, issued to
                        Granite Financial Group, Inc.

      4.14XXX           Callable Warrant, dated June 21, 2001, issued to Millennium
                        Partners, L.P.

      4.15XXX           Common Stock Purchase Warrant, Class A, dated June 21, 2001,
                        issued to Millennium Partners, L.P.

      5.1               Opinion of Ropes & Gray.

     10.1*              Amendment to Registration Rights, dated as of February 14,
                        1992, among the Registrant and certain of its stockholders.

     10.2*              Form of at-will Employment Agreement between the Registrant
                        and most of its employees.

     10.3*              Form of Agreement for Consulting Services between the
                        Registrant and members of its Scientific Advisory Board.

     10.4*              Form of Nondisclosure Agreement between the Registrant and
                        its Contractors.

     10.5*              Master Lease and Warrant Agreement, dated April 23, 1991,
                        between the Registrant and PacifiCorp Credit, Inc.

     10.6*              1988 Stock Option Plan.

     10.7*              1992 Equity Incentive Plan.

     10.8*              1992 Stock Option Plan for Non-Employee Directors.

     10.9**!!!!         1992 Employee Stock Purchase Plan.

     10.12++            Research Agreement, dated as of March 16, 1994, between
                        NeuroSpheres, Ltd. and Registrant.

     10.13++            Term Loan Agreement, dated as of September 30, 1994, between
                        The First National Bank of Boston and Registrant.






       NUMBER                                   DESCRIPTION
---------------------   ------------------------------------------------------------
                     
     10.14++            Lease Agreement between the Registrant and Rhode Island
                        Industrial Facilities Corporation, dated as of August 1,
                        1992.

     10.15++            First Amendment to Lease Agreement between Registrant and
                        The Rhode Island Industrial Facilities Corporation, dated as
                        of September 15, 1994.

     10.17**++++        Development, Marketing and License Agreement, dated as of
                        March 30, 1995 between Registrant and Astra AB.

     10.18++++          Form of Unit Purchase Agreement to be executed by the
                        purchasers of the Common Stock and Warrants offered in April
                        1995.

     10.19+++           Form of Common Stock Purchase Agreement to be executed among
                        the Registrant and certain purchasers of the Registrant's
                        Common Stock.

     10.22###           Lease Agreement, dated as of November 21, 1997, by and
                        between Hub RI Properties Trust, as Landlord, and
                        CytoTherapeutics, Inc., as Tenant.

     10.24!!            CTI individual stockholders option agreement, dated as of
                        July 10, 1996, among the Company and the individuals listed
                        therein.

     10.25!!            CTI Valoria option agreement, dated of July 10, 1996,
                        between the Company and the Societe Financiere Valoria SA.

     10.26!!!           Term Loan Agreement, dated as of October 22, 1996, between
                        The First National Bank of Boston and the Registrant.

     10.27***           Agreement and Plan of Merger, dated as of August 13, 1997,
                        among StemCells, Inc., the Registrant and CTI Acquisition
                        Corp.

     10.28***           Consulting Agreement, dated as of September 25, 1997,
                        between Dr. Irving Weissman and the Registrant.

     10.29###           Letter Agreement among each of Dr. Irving Weissman and Dr.
                        Fred H. Gage and the Registrant.

     10.32****          StemCells, Inc. 1996 Stock Option Plan.

     10.33****          1997 StemCells Research Stock Option Plan (the "1997 Plan").

     10.34****          Form of Performance-Based Incentive Option Agreement issued
                        under the 1997 Plan.

     10.35###           Employment Agreement, dated as of September 25, 1997,
                        between Dr. Richard M. Rose and the Registrant.

     10.38[*]           Rights Agreement, dated as of July 27, 1998, between Bank
                        Boston, N.A. as Rights Agent and the Registrant.

     10.40Section**     Consulting Services Agreement, dated as of July 27, 1998, as
                        amended December 19, 1998, between Dr. John J. Schwartz and
                        the Registrant.

     10.41Section**     Letter Agreement, dated as of December 19, 1998, between
                        John J. Schwartz and the Registrant.

     10.42Section**     License Agreement, dated as of October 27, 1998, between The
                        Scripps Research Institute and the Registrant.

     10.43Section**     License Agreement, dated as of October 27, 1998, between The
                        Scripps Research Institute and the Registrant.

     10.44Section**     License Agreement, dated as of November 20, 1998, between
                        The Scripps Research Institute and the Registrant.

10.45SectionSection**   Purchase Agreement and License Agreement, dated as of
                        December 29, 1999, between Neurotech S.A. and the
                        Registrant.

     10.46**            License Agreement, dated as of June 1999, between The
                        Scripps Research Institute and the Registrant.






       NUMBER                                   DESCRIPTION
---------------------   ------------------------------------------------------------
                     
     10.47**            License Agreement, dated as of June 1999, between The
                        Scripps Research Institute and the Registrant.

     10.48X             Form of Registration Rights Agreement, dated as of July 31,
                        2000, between StemCells, Inc. and investors.

     10.49X             Subscription Agreement, dated as of July 31, 2000, between
                        StemCells, Inc. and Millennium Partners, L.P.

     10.50XXX           Common Stock Purchase Agreement, dated as of May 10, 2001,
                        between the Company and Sativum Investments Limited.

     10.51XXX           Esrow Agreement, dated as of May 10, 2001, among the
                        Company, Sativum Investments Limited and Epstein Becker &
                        Green, P.C.

     10.52XX            License Agreement, dated as of October 30, 2000, between the
                        Company and Neuro Spheres Ltd.

     10.53XX            Letter Agreement, dated January 2, 2001, between the Company
                        and Martin McGlynn.

     10.54XX            Lease, dated February 1, 2001, between the Board of Trustees
                        of Stanford University and the Company.

     10.55XXX           Registration Rights Agreement, dated as of June 21, 2001, by
                        and between the Company and Millennium Partners, L.P.

     10.56XXX           Subscription Agreement, dated as of June 21, 2001, by and
                        between the Company and Millennium Partners, L.P.

  21.1X                 Subsidiaries of the Registrant.

     23.1               Consent of Ernst & Young LLP, Independent Auditors.

     23.2               Consent of Ropes & Gray (included in the opinion filed as
                        Exhibit 5.1).

     24.1               Power of Attorney pursuant to which amendments to this
                        registration statement may be filed (contained on page II-9
                        thereto).

     99.2XX             Side Letter, dated March 17, 2001, between the Company and
                        Oleh S. Hnatiuk regarding NeuroSpheres License Agreement,
                        dated October 30, 2000.


------------------------

++   Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-1, File No. 33-85494.

+++  Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-3, File No. 33-97272.

++++ Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-1, File No. 33-91228.

*      Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, Registration Statement on Form S-1, File
      No. 33-45739.

#     Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      fiscal year ended December 31, 1992 and filed March 30, 1993.

**     Confidential treatment requested as to certain portions. The term
      "confidential treatment" and the mark "**" as used throughout the
      indicated Exhibits mean that material has been omitted and separately
      filed with the Commission.

##   Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Quarterly Report on Form 10-Q for
      the quarter ended March 31, 1994 and filed on May 14, 1994.

+     Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 1993 and filed on March 30, 1994.

!      Previously filed with the Commission as an Exhibit to and incorporated by
      reference to, the Registrant's Quarterly Report on Form 10-Q for the
      quarter ended March 31, 1996.

!!     Previously filed with the Commission as an Exhibit to and incorporated by
      reference to, the Registrant's Quarterly Report on Form 10-Q for the
      quarter ended September 30, 1996.

!!!     Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 1996 and filed on March 31, 1997.

!!!!    Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 1995.

***    Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Quarterly Report on Form 10-Q for
      the quarter ended September 30, 1997 and filed on November 14, 1997.

****   Previously filed with the Commission as Exhibits to, and incorporated
      herein by reference to, the Registrant's Registration Statement on
      Form S-8, File No. 333-37313.

###  Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's annual report on Form 10-K for
      the fiscal year ended December 31, 1997 and filed on March 30, 1998.

[*]    Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's current report on Form 8-K filed
      on August 3, 1998.

Section      Previously filed with the Commission as an Exhibit to, and
      incorporated herein by reference to, the Registrant's annual report on
      Form 10-K for the fiscal year ended December 31, 1998 and filed on
      March 31, 1999.

SectionSection     Previously filed with the Commission as an Exhibit to, and
      incorporated herein by reference to, the Registrant's current report on
      Form 8-K on January 14, 2000

X     Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Registration Statement on Form
      S-1, File No. 333-45496.

XX   Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Annual Report on Form 10-K for
      the fiscal year ended December 31, 2000 and filed on April 2, 2001.

XXX Previously filed with the Commission as an Exhibit to, and incorporated
      herein by reference to, the Registrant's Registration Statement filed on
      Form S-1, File No. 333-61726.