SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                          ----------------------------

                               AMENDMENT NO. 1 TO
                                    FORM 8-A

                FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES
                     PURSUANT TO SECTION 12(b) OR (g) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                           Art Technology Group, Inc.
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             (Exact Name of Registrant as Specified in its Charter)


                                             
            DELAWARE                                      04-3141918
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(State or Other Jurisdiction                             (IRS Employer
       of Incorporation)                                Identification No.)


                      25 First Street, Cambridge, MA 02141
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               (Address of Principal Executive Offices) (Zip Code)

If this form relates to the registration of a class of securities pursuant to
Section 12(b) of the Exchange Act and is effective pursuant to General
Instruction A.(c), please check the following box. [ ]

If this form relates to the registration of a class of securities pursuant to
Section 12(g) of the Exchange Act and is effective pursuant to General
Instruction A.(d), please check the following box. [ X ]

Securities Act registration statement file number to which this form relates:
                                                            NOT APPLICABLE
                                                         --------------------
                                                            (If applicable)

Securities to be registered pursuant to Section 12(b) of the Act:


                                         
       Title of Each Class                     Name of Each Exchange on Which
       to be so Registered                     Each Class is to be Registered
---------------------------------           ------------------------------------


        Securities to be registered pursuant to Section 12(g) of the Act:
                     Common Stock, $.01 par value per share
                     --------------------------------------
                                (Title of Class)



ITEM 1.  DESCRIPTION OF REGISTRANT'S SECURITIES TO BE REGISTERED.

GENERAL

      Our amended and restated certificate of incorporation authorizes the
issuance of up to 500,000,000 shares of common stock, par value $0.01 per share,
and 10,000,000 shares of preferred stock, par value $0.01 per share, of which
100,000 shares are designated Series A Junior Participating Preferred Stock in
connection with the Rights Plan described below. The rights and preferences of
the remaining authorized preferred stock may be established from time to time by
our board of directors. As of September 28, 2001, 68,822,007 shares of common
stock were outstanding and we had approximately 242 stockholders of record. No
shares of Series A Junior Participating Preferred Stock are outstanding as of
the date of this filing. The following description of the capital stock of the
Registrant is qualified in its entirety by reference to our amended and restated
certificate of incorporation, as amended (the "Certificate of Incorporation"),
and amended and restated bylaws (the "Bylaws"), copies of which have been filed
with the Securities and Exchange Commission.

COMMON STOCK

      Holders of common stock are entitled to one vote for each share held on
all matters submitted to a vote of stockholders and do not have cumulative
voting rights. Accordingly, holders of a majority of the shares of common stock
entitled to vote in any election of directors may elect all of the directors
standing for election. Holders of common stock are entitled to receive
proportionately any dividends as may be declared by our board of directors,
subject to any preferential dividend rights of outstanding preferred stock. Upon
our liquidation, dissolution or winding up, the holders of common stock are
entitled to receive proportionately our net assets available after the payment
of all debts and other liabilities and subject to the prior rights of any
outstanding preferred stock. Holders of common stock have no preemptive,
subscription, redemption or conversion rights, other than described below under
the caption "Rights Plan". The rights, preferences and privileges of holders of
common stock are subject to, and may be adversely affected by, the rights of the
holders of shares of any series of preferred stock which we may designate and
issue in the future.

      For a description of the purchase rights held by the holders of common
stock on and after October 9, 2001, please see the information under the caption
"Rights Plan" below.

PREFERRED STOCK

      Under the terms of our Certificate of Incorporation, our board of
directors is authorized to issue shares of preferred stock in one or more series
without stockholder approval. Our board of directors has the discretion to
determine the rights, preferences, privileges and restrictions, including voting
rights, dividend rights, conversion rights, redemption privileges and
liquidation preferences, of each series of preferred stock. On September 26,
2001, in connection with the Rights Plan described below, our board of directors
designated 100,000 shares of preferred stock as Series A Junior Participating
Preferred Stock, $.01 par value per share, as set forth in the Certificate of
Designations of Series A Junior Participating Preferred Stock filed with the
Secretary of State of the State of Delaware on September 28, 2001 and summarized
below under the caption "Rights Plan".

      The purpose of authorizing our board of directors to issue preferred stock
and determine its rights and preferences is to eliminate delays associated with
a stockholder vote on specific issuances. The issuance of preferred stock may
provide desirable flexibility in connection with possible acquisitions and

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other corporate purposes, but could have the effect of making it more difficult
for a third party to acquire, or could discourage a third party from acquiring,
a majority of our outstanding voting stock.

RIGHTS PLAN

      On September 26, 2001, our board of directors declared a dividend of one
Right for each outstanding share of our common stock to stockholders of record
at the close of business on October 9, 2001 (the "Record Date"). Each Right
entitles the registered holder to purchase from us one one-thousandth of a share
of Series A Junior Participating Preferred Stock, $.01 par value per share (the
"Preferred Stock"), at a Purchase Price of $15.00 in cash, subject to
adjustment. The description and terms of the Rights are set forth in a Rights
Agreement dated September 26, 2001 (the "Rights Agreement") between us and
EquiServe, L.P., as Rights Agent.

      Initially, the Rights are not exercisable and will be attached to all
certificates representing outstanding shares of common stock, and no separate
Rights Certificates will be distributed. The Rights will separate from the
common stock, and the Distribution Date will occur, upon the earlier of (i) 10
business days following the later of (a) the first date of a public announcement
that a person or group of affiliated or associated persons (an "Acquiring
Person") has acquired, or obtained the right to acquire, beneficial ownership of
15% or more of the outstanding shares of common stock or (b) the first date on
which an executive officer of our company has actual knowledge that an Acquiring
Person has become such (the "Stock Acquisition Date"), or (ii) 10 business days
following the commencement of a tender offer or exchange offer that would result
in a person or group beneficially owning 15% or more of the outstanding shares
of common stock. The Distribution Date may be deferred in circumstances
determined by the board of directors. In addition, certain inadvertent
acquisitions will not trigger the occurrence of the Distribution Date. Until the
Distribution Date (or earlier redemption or expiration of the Rights), (i) the
Rights will be evidenced by the common stock certificates outstanding on the
Record Date, together with this Summary of Rights, or by new common stock
certificates issued after the Record Date which contain a notation incorporating
the Rights Agreement by reference, (ii) the Rights will be transferred with and
only with such common stock certificates; and (iii) the surrender for transfer
of any certificates for common stock outstanding (with or without a copy of this
Summary of Rights or such notation) will also constitute the transfer of the
Rights associated with the common stock represented by such certificate.

      The Rights are not exercisable until the Distribution Date and will expire
upon the close of business on September 26, 2011 (the "Final Expiration Date")
unless earlier redeemed or exchanged as described below. As soon as practicable
after the Distribution Date, separate Rights Certificates will be mailed to
holders of record of the common stock as of the close of business on the
Distribution Date and, thereafter, the separate Rights Certificates alone will
represent the Rights. Except as otherwise determined by the board of directors,
and except for shares of common stock issued upon exercise, conversion or
exchange of then outstanding options, convertible or exchangeable securities or
other contingent obligations to issue shares or pursuant to any employee benefit
plan or arrangement, only shares of common stock issued prior to the
Distribution Date will be issued with Rights.

      In the event that any Person becomes an Acquiring Person, unless the event
causing the 15% threshold to be crossed is a Permitted Offer (as defined in the
Rights Agreement), then, promptly following the first occurrence of such event,
each holder of a Right (except as provided below and in Section 7(e) of the
Rights Agreement) shall thereafter have the right to receive, upon exercise,
that number of shares of common stock of ATG (or, in certain circumstances,
cash, property or other securities of the ATG) which equals the exercise price
of the Right divided by 50% of the current market price (as defined in the
Rights Agreement) per share of common stock at the date of the occurrence of
such event. However, Rights are not exercisable following such event until such
time as the Rights are no

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longer redeemable by us as described below. Notwithstanding any of the
foregoing, following the occurrence of such event, all Rights that are, or
(under certain circumstances specified in the Rights Agreement) were,
beneficially owned by any Acquiring Person will be null and void. The event
summarized in this paragraph is referred to as a "Section 11(a)(ii) Event."

      For example, at an exercise price of $15 per Right, each Right not
owned by an Acquiring Person (or by certain related parties) following a
Section 11(a)(ii) Event would entitle its holder to purchase for $15 such
number of shares of common stock (or other consideration, as noted above) as
equals $15 divided by one-half of the current market price (as defined in the
Rights Agreement) of the common stock. Assuming that the common stock had a
market price of $7.50 per share at such time, the holder of each valid Right
would be entitled to purchase four shares of common stock, having a market
value of 4 x $7.50, or $30, for $15.

      In the event that, at any time after any Person becomes an Acquiring
Person, (i) ATG is consolidated with, or merged with and into, another entity
and ATG is not the surviving entity of such consolidation or merger (other than
a consolidation or merger which follows a Permitted Offer) or if ATG is the
surviving entity, but shares of its outstanding common stock are changed or
exchanged for stock or securities (of any other person) or cash or any other
property, or (ii) more than 50% of the ATG's assets or earning power is sold or
transferred, each holder of a Right (except Rights which previously have been
voided as set forth above) shall thereafter have the right to receive, upon
exercise, that number of shares of common stock of the acquiring company which
equals the exercise price of the Right divided by 50% of the current market
price (as defined in the Rights Agreement) of such common stock at the date of
the occurrence of the event. The events summarized in this paragraph are
referred to as "Section 13 Events." A Section 11(a)(ii) Event and Section 13
Events are collectively referred to as "Triggering Events."

      For example, at an exercise price of $15 per Right, each valid Right
following a Section 13 Event would entitle its holder to purchase for $15 such
number of shares of common stock of the acquiring company as equals $15 divided
by one-half of the current market price (as defined in the Rights Agreement) of
such common stock. Assuming that such common stock had a market price of $7.50
per share at such time, the holder of each valid Right would be entitled to
purchase four shares of common stock of the acquiring company, having a market
value of 4 x $7.50, or $30, for $15.

      At any time after the occurrence of a Section 11(a)(ii) Event, when no
person owns a majority of the common stock, the board of directors of ATG may
exchange the Rights (other than Rights owned by such Acquiring Person which have
become void), in whole or in part, at an exchange ratio of one share of common
stock, or one one-thousandth of a share of Preferred Stock (or of a share of a
class or series of the ATG's preferred stock having equivalent rights,
preferences and privileges), per Right (subject to adjustment).

      The Purchase Price payable, and the number of units of Preferred Stock or
other securities or property issuable, upon exercise of the Rights are subject
to adjustment from time to time to prevent dilution (i) in the event of a stock
dividend on, or a subdivision, combination or reclassification of, the Preferred
Stock, (ii) if holders of the Preferred Stock are granted certain rights or
warrants to subscribe for Preferred Stock or convertible securities at less than
the then-current market price (as defined in the Rights Agreement) of the
Preferred Stock, or (iii) upon the distribution to holders of the Preferred
Stock of evidences of indebtedness or assets (excluding regular periodic cash
dividends paid out of earnings or retained earnings) or of subscription rights
or warrants (other than those referred to above). The number of Rights
associated with each share of common stock is also subject to adjustment in the
event of a stock split of the common stock or a stock dividend on the common
stock payable in common stock or subdivisions, consolidations or combinations of
the common stock occurring, in any such case, prior to the Distribution Date.

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      With certain exceptions, no adjustment in the Purchase Price will be
required until cumulative adjustments amount to at least 1% of the Purchase
Price. No fractional shares of Preferred Stock (other than fractions which are
integral multiples of one one-thousandth of a share of Preferred Stock) will be
issued and, in lieu thereof, an adjustment in cash will be made based on the
market price of the Preferred Stock on the last trading date prior to the date
of exercise.

      Preferred Stock purchasable upon exercise of the Rights will not be
redeemable. Each share of Preferred Stock will be entitled to receive, when, as
and if declared by the board of directors, a minimum preferential quarterly
dividend payment of $10 per share or, if greater, an aggregate dividend of 1000
times the dividend declared per share of common stock. In the event of
liquidation, the holders of the Preferred Stock will be entitled to a minimum
preferential liquidation payment of $1000 per share, plus an amount equal to
accrued and unpaid dividends, and will be entitled to an aggregate payment of
1000 times the payment made per share of common stock. Each share of Preferred
Stock will have 1000 votes, voting together with the common stock. In the event
of any merger, consolidation or other transaction in which common stock is
changed or exchanged, each share of Preferred Stock will be entitled to receive
1000 times the amount received per share of common stock. These rights are
protected by customary antidilution provisions. Because of the nature of the
Preferred Stock's dividend, liquidation and voting rights, the value of one
one-thousandth of a share of Preferred Stock purchasable upon exercise of each
Right should approximate the value of one share of Common Stock.

      At any time prior to the earlier of the tenth Business Day (or such later
date as may be determined by the Board of Directors of the Company) after the
Stock Acquisition Date, the Company may redeem the Rights in whole, but not in
part, at a price of $0.001 per Right (the "Redemption Price"), payable in cash
or stock. Immediately upon the redemption of the Rights or such earlier time as
established by the Board in the resolution ordering the redemption of the
Rights, the Rights will terminate and the only right of the holders of Rights
will be to receive the Redemption Price. The Rights may also be redeemable
following certain other circumstances specified in the Rights Agreement.

      Until a Right is exercised, the holder thereof, as such, will have no
rights as a stockholder of the Company, including, without limitation, the right
to vote or to receive dividends. Although the distribution of the Rights should
not be taxable to stockholders or to ATG, stockholders may, depending upon the
circumstances, recognize taxable income in the event that the Rights become
exercisable for common stock (or other consideration) of ATG or for common stock
of the acquiring company as set forth above.

      Any provision of the Rights Agreement, other than the redemption price,
may be amended by the board of directors prior to such time as the Rights are no
longer redeemable. Once the Rights are no longer redeemable, the board's
authority to amend the Rights is limited to correcting ambiguities or defective
or inconsistent provisions in a manner that does not adversely affect the
interest of holders of Rights.

      The Rights are intended to protect the stockholders of ATG in the event of
an unfair or coercive offer to acquire ATG and to provide the board with
adequate time to evaluate unsolicited offers. The Rights may have anti-takeover
effects. The Rights will cause substantial dilution to a person or group that
attempts to acquire ATG without conditioning the offer on a substantial number
of Rights being acquired. The Rights, however, should not affect any prospective
offeror willing to make an offer at a fair price and otherwise in the best
interests of ATG and its stockholders, as determined by a majority of the board.
The Rights should not interfere with any merger or other business combination
approved by the board.

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      A copy of the Rights Agreement is available free of charge from ATG. This
summary description of the Rights does not purport to be complete and is
qualified in its entirety by reference to the Rights Agreement, which is
attached as Exhibit 4.1 and incorporated herein by reference.

DELAWARE LAW AND OUR CHARTER AND BY-LAWS PROVISIONS

      We are subject to the provisions of Section 203 of the General Corporation
Law of Delaware. Section 203 prohibits a publicly held Delaware corporation from
engaging in a business combination with an interested stockholder for a period
of three years after the person became an interested stockholder, unless the
business combination is approved in a prescribed manner. A business combination
includes mergers, asset sales and other transactions resulting in a financial
benefit to the interested stockholder. An interested stockholder generally is a
person who, together with affiliates and associates, owns, or within the prior
three years did own, 15% or more of the corporation's voting stock.

      Our Certificate of Incorporation divides our board of directors into three
classes with staggered three-year terms. In addition, our Certificate of
Incorporation provides that directors may be removed only for cause by the
affirmative vote of the holders of two-thirds of our shares of capital stock
entitled to vote. Under our Certificate of Incorporation, any vacancy on our
board of directors, including a vacancy resulting from an enlargement of our
board of directors, may only be filled by vote of a majority of our directors
then in office. The classification of our board of directors and the limitations
on the removal of directors and filling of vacancies could make it more
difficult for a third party to acquire, or discourage a third party from
acquiring, control of the company.

      Our Certificate of Incorporation also provides that any action required or
permitted to be taken by our stockholders at an annual meeting or special
meeting of stockholders may only be taken if it is properly brought before the
meeting and may not be taken by written action in lieu of a meeting. Our
Certificate of Incorporation further provides that special meetings of the
stockholders may only be called by our Chairman of the Board, President or board
of directors. Under our Bylaws, in order for any matter to be considered
properly brought before a meeting, a stockholder must comply with advance notice
requirements. These provisions could have the effect of delaying until the next
stockholders' meeting stockholder actions which are favored by the holders of a
majority of our outstanding voting securities. These provisions may also
discourage a third party from making a tender offer for our common stock,
because even if it acquired a majority of our outstanding voting securities, the
third party would be able to take action as a stockholder (such as electing new
directors or approving a merger) only at a duly called stockholders' meeting,
and not by written consent.

      The General Corporation Law of Delaware provides generally that the
affirmative vote of a majority of the shares entitled to vote on any matter is
required to amend a corporation's certificate of incorporation or by-laws,
unless a corporation's Certificate of Incorporation or Bylaws, as the case may
be, requires a greater percentage. Our certificate of incorporation and bylaws
require the affirmative vote of the holders of at least 75% of the shares of our
capital stock issued and outstanding and entitled to vote to amend or repeal any
of the provisions described in the prior two paragraphs.

      Our Certificate of Incorporation contains provisions permitted under the
General Corporation Law of Delaware relating to the liability of directors. The
provisions eliminate a director's liability for monetary damages for a breach of
fiduciary duty, except in circumstances involving wrongful acts, such as the
breach of a director's duty of loyalty or acts or omissions that involve
intentional misconduct or a knowing violation of law. Further, our Certificate
of Incorporation contains provisions to indemnify our directors and officers to
the fullest extent permitted by the General Corporation Law of Delaware. We
believe that these provisions will assist us in attracting and retaining
qualified individuals to serve as directors.

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TRANSFER AGENT AND REGISTRAR

The transfer agent and registrar for our common stock is Continental Stock
Transfer & Trust.

ITEM 2: EXHIBITS.



EXHIBIT NUMBER    DESCRIPTION
               
            1     Amended and Restated Certificate of Incorporation of the Registrant (incorporated
                  by reference to the Company's Registration Statement on Form S-1
                  (File No. 333-78333) as declared effective by the SEC on July 20, 1999).

            2     Amendment, dated June 7, 2000, to the Amended and Restated Certificate of
                  Incorporation of the Registrant (incorporated by reference to the
                  Company's Registration Statement on Form S-8 (File No. 333-38926) as declared
                  effective by the SEC on June 9, 2000.

            3     Amended and Restated Bylaws of the Registrant (incorporated by reference to
                  the Company's Registration Statement on Form S-1 (File No. 333-78333) as
                  declared effective by the SEC on July 20, 1999).

            4     Rights Agreement dated September 26, 2001 between the Registrant and
                  EquiServe Trust Company, N.A., as Rights Agent, which includes as Exhibit A the
                  Form of Certificate of Designations of Series A Junior Participating Preferred
                  Stock, as Exhibit B the Form of Rights Certificate and as Exhibit C the Summary of
                  Rights to Purchase Common Stock (incorporated by reference to the Company's
                  Current Report on Form 8-K filed with the SEC on October 2, 2001).





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                                    SIGNATURE

Pursuant to the requirements of Section 12 of the Securities Exchange Act of
1934, the Registrant has duly caused this Amendment No. 1 to registration
statement to be signed on its behalf by the undersigned, thereunto duly
authorized, on this 28th day of September, 2001.

                                        ART TECHNOLOGY GROUP, INC.

                                        By: /s/ Joseph T. Chung
                                            -----------------------------------


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