Filed Pursuant to Rule 424(b)(5)
Reg. Statement No. 333-137225

SUBJECT TO COMPLETION DATED OCTOBER 30, 2006

The information in this prospectus supplement and the accompanying prospectus is not complete and may be changed. This prospectus supplement and the accompanying prospectus are not offers to sell these securities, and we are not soliciting offers to buy these securities in any state or jurisdiction where the offer or sale is not permitted.

Prospectus Supplement
(To Prospectus dated September 8, 2006)

22,000,000 Shares

Health Care Property Investors, Inc.

Common Stock

We are offering 22,000,000 shares of our common stock to the public. Our common stock is traded on the New York Stock Exchange under the symbol “HCP.”  The last reported sale price of our common stock on the New York Stock Exchange on October 26, 2006 was $31.74 per share.

Investing in our common stock involves risk. See “Risk Factors” beginning on page S-7 of this prospectus supplement and page 4 of the accompanying prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined that this prospectus supplement or the accompanying prospectus is accurate or complete. Any representation to the contrary is a criminal offense.

The underwriters have a 30-day option to purchase up to 3,300,000 additional shares of common stock from us on the same terms and conditions set forth above. The option may be exercised solely to cover over-allotments, if any.

November    , 2006

You should rely only on the information contained or incorporated by reference in this prospectus supplement or the accompanying prospectus. We have not authorized anyone to provide you with information that is different. We are not making an offer to sell these securities in any jurisdiction where the offer or sale of these securities is not permitted. This document may only be used where it is legal to sell these securities. You should assume that the information in this prospectus supplement and the accompanying prospectus is accurate only as of their respective dates and that any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference.

All references in this prospectus supplement to “HCP,” “we,” “us” or “our” mean Health Care Property Investors, Inc., its majority-owned subsidiaries and other entities controlled by Health Care Property Investors, Inc. except where it is clear from the context that the term means only the issuer, Health Care Property Investors, Inc. Unless otherwise stated, currency amounts in this prospectus supplement are stated in United States dollars.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first is this prospectus supplement, which describes the specific terms of this offering. The second part, the accompanying prospectus, gives more general information, some of which may not apply to this offering. This prospectus supplement also adds to, updates and changes information contained in the accompanying prospectus. If the description of the offering varies between this prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement. The accompanying prospectus is part of a registration statement that we filed with the Securities and Exchange Commission using a shelf registration statement. Under the shelf registration process, from time to time, we may offer and sell debt securities, warrants or other rights, stock purchase contracts, units, common stock, preferred stock or depositary shares, or any combination thereof, in one or more offerings.

It is important that you read and consider all of the information contained in this prospectus supplement and the accompanying prospectus in making your investment decision. You should also read and consider the information in the documents to which we have referred you in “Incorporation by Reference” on page S-2 of this prospectus supplement and “Where You Can Find More Information” on page 2 of the accompanying prospectus.

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INCORPORATION BY REFERENCE

The Securities and Exchange Commission, or SEC, allows us to “incorporate by reference” information into this prospectus supplement and the accompanying prospectus. This means that we can disclose important information to you by referring you to another document that HCP has filed separately with the SEC that contains that information. The information incorporated by reference is considered to be part of this prospectus supplement and the accompanying prospectus. Information that HCP files with the SEC after the date of this prospectus supplement will automatically modify and supersede the information included or incorporated by reference in this prospectus supplement and the accompanying prospectus to the extent that the subsequently filed information modifies or supersedes the existing information. We incorporate by reference (other than any portions of any such documents that are not deemed “filed” under the Securities Exchange Act of 1934 in accordance with the Securities Exchange Act of 1934 and applicable SEC rules):

·       our Current Reports on Form 8-K filed on February 9, 2006, February 17, 2006, February 21, 2006, May 2, 2006 (pursuant to Items 8.01 and 9.01), May 4, 2006, May 17, 2006, June 30, 2006, August 2, 2006, August 4, 2006 and August 17, 2006, the two Current Reports on Form 8-K filed on September 8, 2006 and the Current Reports filed on September 19, 2006, September 25, 2006 and October 12, 2006;

·       our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2006, June 30, 2006 and September 30, 2006;

·       our Annual Report on Form 10-K for the fiscal year ended December 31, 2005;

·       the description of our common stock contained in our registration statement on Form 10 dated May 7, 1985 (File No. 1-8895), including the amendments dated May 20, 1985 and May 23, 1985, and any other amendment or report filed for the purpose of updating such description, including the description of amendments to our charter contained in our Quarterly Reports on Form 10-Q for the quarters ended June 30, 2001 and June 30, 2004; and

·       any future filings we make with the SEC under Sections 13(a), l3(c), 14 or 15(d) of the Securities Exchange Act of 1934 until we sell all of the securities offered by this prospectus supplement.

You may request a copy of any of these filings at no cost by writing to or telephoning us at the following address and telephone number:

Legal Department
Health Care Property Investors, Inc.
3760 Kilroy Airport Way, Suite 300
Long Beach, California 90806
(562) 733-5100
legaldept@hcpi.com

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SUMMARY

The information below is a summary of the more detailed information included elsewhere in or incorporated by reference in this prospectus supplement. You should read carefully the following summary together with the more detailed information contained in this prospectus supplement, including the “Risk Factors” section beginning on page S-7, the accompanying prospectus, including the “Risk Factors” section beginning on page 4, and the information incorporated by reference. This summary is not complete and does not contain all of the information you should consider before purchasing the common stock.

Our Company

We invest primarily in real estate serving the healthcare industry in the United States. We are a Maryland corporation and were organized to qualify as a real estate investment trust, or REIT, in 1985. We are headquartered in Long Beach, California, with operations in Nashville, Tennessee. As of September 30, 2006, our portfolio of properties, excluding assets held for sale but including investments through joint ventures and mortgage loans, included 521 properties in 42 states and consisted of 144 senior housing facilities, 178 medical office buildings, 30 hospitals, 144 skilled nursing facilities and 25 other healthcare facilities. We acquire healthcare facilities and lease them to healthcare providers and provide mortgage financing secured by healthcare facilities. Our portfolio includes:

·       senior housing, including independent living facilities, assisted living facilities, and continuing care retirement communities;

·       medical office buildings;

·       hospitals;

·       skilled nursing facilities; and

·       other healthcare facilities, including laboratory and office buildings.

Our executive offices are located at 3760 Kilroy Airport Way, Suite 300, Long Beach, California 90806, and our telephone number is (562) 733-5100.

Healthcare Industry

In 2004, healthcare was the single largest industry in the United States, representing 16.0% of U.S. Gross Domestic Product and growing at a rate faster than the overall economy, according to data made available by the U.S. Bureau of Labor Statistics and the Centers for Medicare and Medicaid.

The delivery of healthcare services requires real estate and as a consequence, healthcare providers depend on real estate to maintain and grow their businesses. HCP believes that the current healthcare real estate market provides an investment opportunity for investors based on:

·       Likelihood of consolidation of the fragmented healthcare real estate sector;

·       Specialized nature of healthcare real estate investing; and

·       Compelling demographics driving the demand for healthcare services.

Senior citizens are the largest consumers of healthcare services. According to the Centers for Medicare and Medicaid, on a per capita basis, the 75 years and older segment of the population spends 75% more on healthcare than the 65 to 74-year-old segment and nearly 300% more than the population average.

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Recent Developments

On October 5, 2006, HCP acquired CNL Retirement Properties, Inc., or CRP. CRP was a REIT that was one of the nation’s largest investors in healthcare-related real estate, investing primarily in properties related to senior housing and healthcare facilities located across the United States. As of September 30, 2006, CRP had 273 properties located in 33 states, consisting of 184 senior housing facilities and 89 medical facilities, including two specialty hospitals and two walk-in clinics. Following the acquisition, HCP currently owns approximately 800 properties. HCP believes that the transaction diversified its portfolio by property type, geographic location and operator, and that it diversified its source of revenues across the healthcare industry. HCP also believes that its shift in asset mix improved the quality of HCP’s real estate portfolio by increasing, among other things, its exposure to private-pay senior housing.

As of September 30, 2006, HCP’s portfolio of healthcare real estate was comprised of approximately 28% medical office buildings, 34% senior housing facilities, 19% hospitals, and 14% skilled nursing facilities, with the remaining 5% comprised of other types of buildings, based on HCP’s historical cost of real estate investments and the carrying amount of investments in unconsolidated joint ventures. As of September 30, 2006 on a pro forma basis, assuming that the acquisition of CRP had occurred as of that date, HCP’s portfolio of healthcare real estate would have been comprised of approximately 23% medical office buildings, 59% senior housing facilities, 9% hospitals, and 6% skilled nursing facilities, with the remaining 3% comprised of other types of buildings, based on HCP’s historical cost of real estate investments and the carrying amount of investments in unconsolidated joint ventures and as adjusted for the preliminary allocation of the purchase price for CRP.

In the acquisition, HCP paid an aggregate of $2.9 billion in cash and issued 22.9 million shares of common stock. HCP also acquired CNL Retirement Corp., the external advisor to CRP, or the Advisor, for an aggregate of 4.4 million shares of common stock. HCP financed the cash consideration paid to CRP stockholders and the expenses related to the transaction through an offering of notes and a draw down under new term and bridge loan facilities and a new three-year revolving credit facility. These facilities require refinancing within a period of time ranging from 364 days to three years and the new term and bridge loan facilities are required to be repaid from the cash proceeds of non-ordinary course asset sales, the incurrence of certain debt, the issuance of additional equity and certain other events. Certain of HCP’s subsidiaries, including certain of CRP’s subsidiaries, guarantee HCP’s obligations under these new facilities. The interest rates on borrowings under these facilities vary depending on HCP’s credit ratings.

On October 24, 2006, we entered into a definitive agreement to acquire the interest of an affiliate of General Electric Company in HCP Medical Office Portfolio, LLC for $141 million. The closing of the transaction is subject to certain customary conditions. Upon the closing of this acquisition, which we expect to occur on or before November 30, 2006, we will be the sole owner of the venture and its fifty-nine medical office buildings with approximately 4 million rentable square feet.

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The Offering

(1)                 Based on shares of our common stock outstanding as of October 23, 2006. Does not include:

·        4.4 million shares of common stock issuable upon the exercise of outstanding options;

·        8.3 million additional shares reserved for future awards under stock incentive plans;

·        up to 3.3 million shares issuable upon exercise of the underwriters’ over-allotment option; and

·        6.0 million shares of common stock issuable in exchange for non-managing member units of affiliated entities.

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SUMMARY CONSOLIDATED FINANCIAL DATA

The following table sets forth our summary consolidated financial data. You should read this information together with our financial statements, including the related notes, included in our Quarterly Report on Form 10-Q for the quarter ended September 30, 2006 from which such information has been derived. The summary consolidated balance sheet data as of December 31, 2005 has been derived from our Annual Report on Form 10-K for the year ended December 31, 2005. Our unaudited summary consolidated financial data as of September 30, 2006 and for the three and nine months ended September 30, 2005 and 2006 has been prepared on the same basis as our annual consolidated financial statements and includes all adjustments, consisting of only normal recurring adjustments necessary for the fair presentation of this data in all material respects. The results for any interim period are not necessarily indicative of the results of operations to be expected for a full fiscal year.

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RISK FACTORS

Before purchasing our common stock, you should consider carefully the information under the heading “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2005, in our Quarterly Report on Form 10-Q for the quarter ended September 30, 2006, in the accompanying prospectus and the following factors, each of which could materially adversely affect our operating results and financial condition. You should also carefully consider the other information included in this prospectus supplement, the accompanying prospectus and other information incorporated by reference herein. Each of the risks described in our Form 10-K, Form 10-Q and the accompanying prospectus and below could result in a decrease in the value of our common stock and your investment therein. Although we have tried to discuss what we believe are key risk factors, please be aware that other risks may prove to be important in the future. New risks may emerge at any time, and we cannot predict those risks or estimate the extent to which they may affect our financial performance or the market value of our common stock. The information contained, and incorporated by reference, in this prospectus supplement and in the accompanying prospectus includes forward-looking statements that involve risks and uncertainties, and we refer you to the “Cautionary Language Regarding Forward-Looking Statements” section in the accompanying prospectus.

Risks Related to Our Common Stock

The market value of our common stock could be substantially affected by various factors.

The market value of our common stock will depend on many factors, which may change from time to time, including:

·       prevailing interest rates, increases in which may have an adverse effect on the market value of our common stock;

·       the market for similar securities issued by other REITs;

·       general economic and financial market conditions;

·       the financial condition, performance and prospects of us and our competitors;

·       changes in financial estimates or recommendations by securities analysts with respect to us, our competitors or our industry;

·       changes in our credit ratings; and

·       actual or anticipated variations in quarterly operating results.

As a result of these and other factors, investors who purchase our common stock in this offering may experience a decrease, which could be substantial, in the market value of our common stock, including decreases unrelated to our operating performance or prospects.

Increases in market interest rates may adversely affect the price of our common stock.

One of the factors that influences the price of our common stock in public trading markets is the annual yield from distributions on our common stock as compared to yields on other financial instruments. Thus, an increase in market interest rates will result in higher yields on other financial instruments, which could adversely affect the market price of our common stock.

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USE OF PROCEEDS

We anticipate that the net proceeds from this offering, after deducting underwriting discounts and estimated expenses payable by us, will be approximately $                      , or $                   if the underwriters exercise their over-allotment option in full. We intend to use the proceeds from this offering to repay indebtedness under our 364-day bridge loan facility incurred in connection with the acquisition of CRP.

As of October 26, 2006, the interest rate was 6.17% on the debt under the bridge facility, which matures on October 3, 2007. Debt under the bridge facility was incurred to finance the mergers with CRP and the Advisor.

If the net proceeds from this offering exceed the amount of borrowings outstanding under the bridge loan facility, the net proceeds remaining after repayment of all bridge loan borrowings will be used for repayment of other debt or other general corporate purposes.

Affiliates of certain of the underwriters are lenders under our credit facilities, including the bridge facility, and therefore will receive a portion of the net proceeds from the offering through the repayment of debt under one or more of those facilities.

PRICE RANGE OF COMMON STOCK AND DIVIDENDS

Our common stock is listed on the NYSE under the symbol “HCP.”  The table below sets forth for the fiscal quarters indicated high and low reported closing sale prices per share of the common stock on the NYSE for the periods indicated and the cash dividends per share paid in such periods. The last reported sale price of our common stock on the NYSE on October 26, 2006 was $31.74 per share.

As of September 30, 2006, there were approximately 2,578 stockholders of record.

We maintain a policy to declare dividends to the holders of shares of our common stock so as to comply with applicable sections of the Internal Revenue Code governing real estate investments trusts.

Our board of directors has declared a quarterly dividend of $0.425 per share of common stock, payable on November 21, 2006 to stockholders of record as of the close of business on November 3, 2006. The shares of common stock sold in this offering will not be entitled to receive this November 21, 2006 dividend.

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CAPITALIZATION

The following table sets forth the capitalization of HCP as of September 30, 2006 on an actual basis, on a pro forma basis to give effect to the acquisitions of CRP and the Advisor and the issuance of common stock and the incurrence of debt in connection therewith as described under “Summary — Recent Developments” as if those acquisitions, issuances of common stock and incurrences of debt had occurred on that date, and on a pro forma as adjusted basis to give effect to those acquisitions, issuances and incurrences and this offering of common stock and the application of the net proceeds from this offering to repay borrowings as if they had occurred on that date. This table should be read together with our consolidated financial statements and related notes contained in our Quarterly Report on Form 10-Q for the quarter ended September 30, 2006.

(1)                 Interest on our three-year line of credit, 364-day bridge facility and two-year term facility is variable based on LIBOR.

(2)                 Interest rates on the senior unsecured notes ranged from 4.88% to 7.62% with a weighted average effective rate of 6.06% at September 30, 2006.

(3)                 Interest rates on mortgage debt ranged from 3.75% to 9.32% with a weighted average effective rate of 6.44% at September 30, 2006.

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UNAUDITED PRO FORMA CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

The following is an excerpt of information contained in our Current Report on Form 8-K as filed with the SEC on September 8, 2006 and incorporated herein by reference. This information speaks only as of September 8, 2006 and has not been updated for, and does not reflect, any events since that date. These events include:

·       the closing of the mergers with CRP and the Advisor, which occurred on October 5, 2006;

·       the respective amounts of the various types of debt that we actually incurred through the issuance of senior notes and pursuant to our bridge and note facilities and mortgage debt;

·       changes in interest rates;

·       actual number of shares issued in the merger with CRP;

·       actual costs and expenses incurred in connection with the merger with CRP and the Advisor;

·       the results of operations for HCP, CRP and the Advisor for the three months ended September 30, 2006 and changes in the balance sheets for those companies as of September 30, 2006;

·       the reclassification of 14 HCP properties into discontinued operations in the financial statements of HCP, which is reflected in HCP’s financial statements in its Quarterly Report on Form 10-Q for the quarter ended September 30, 2006 but which is not reflected in the HCP historical financial information appearing below; and

·       this offering and the application of the proceeds.

These subsequent events, in some cases, are different than the assumptions set forth below and would affect the financial information presented and accompanying disclosure, in some cases significantly.

Accordingly, you should not rely on this information as reflecting current information regarding HCP, CRP, the Advisor or the merger. You should also read this information together with all the other information contained or incorporated by reference in this prospectus supplement after September 8, 2006. In addition, to the extent that any of the following information includes references to “current” or “present” facts or circumstances or similar references, it is referring to facts and circumstances that existed at the time this information was prepared and, to the extent that any of the following information includes references to expectations, future events, future circumstances or similar references, it is referring to expectations and estimates as of the time this information was prepared.

Excerpt from Current Report on Form 8-K filed on September 8, 2006:

The unaudited pro forma condensed consolidated financial statements presented below have been prepared based on certain pro forma adjustments to the historical consolidated financial statements of HCP, CRP and the Advisor as of and for the six months ended June 30, 2006 and for the year ended December 31, 2005. The historical consolidated financial statements of HCP are contained in its Annual Report on Form 10-K for the year ended December 31, 2005, Quarterly Report on Form 10-Q for the quarter ended June 30, 2006 and Current Report on Form 8-K as filed on September 8, 2006 with the SEC. The historical consolidated financial statements of CRP and the Advisor are included as Exhibits 99.3, 99.4, 99.5 and 99.6 to the Current Report on Form 8-K referred to in the preceding sentence. The historical financial information with respect to HCP and CRP for the year ended December 31, 2005 has been restated to reflect as discontinued operations the results of operations of certain properties that were initially classified as discontinued operations during the six months ended June 30, 2006. The unaudited pro forma condensed consolidated financial statements relate to the proposed merger of CRP with and into Ocean Acquisition 1, Inc., a wholly owned subsidiary of HCP, which is referred to in this section as the Merger, and the proposed merger of the Advisor with and into Ocean Acquisition 2, LLC, a wholly owned

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subsidiary of HCP, which is referred to in this section as the Advisor Merger. The accompanying unaudited pro forma condensed consolidated balance sheet as of June 30, 2006 has been prepared as if the Merger and the Advisor Merger and the incurrence of debt by HCP to finance the acquisitions of CRP and the Advisor had occurred as of that date.

The accompanying unaudited pro forma condensed consolidated statements of income for the six months ended June 30, 2006 and for the year ended December 31, 2005 have been prepared as if the Merger and the Advisor Merger had occurred as of January 1, 2005 and reflects the incurrence of debt by HCP in order to finance the acquisition of CRP, including the cash consideration needed for the Merger. The allocation of the purchase price of CRP and the Advisor as reflected in these unaudited pro forma condensed consolidated financial statements has, with the assistance of independent valuation specialists, been based upon preliminary estimates of the fair value of assets acquired and liabilities assumed. In the opinion of HCP’s management, all significant adjustments necessary to reflect the effects of the Merger and the Advisor Merger that can be factually supported within the SEC regulations covering the preparation of pro forma financial statements have been made.

A final determination of the fair values of CRP’s and the Advisor’s assets and liabilities, which cannot be made prior to the completion of the transactions, will be based on the actual net tangible and intangible assets of CRP and the Advisor that exist as of the date of completion of the transactions. Consequently, amounts preliminarily allocated to goodwill and identifiable intangibles could change significantly from those used in the pro forma condensed consolidated financial statements presented below and could result in a material change in amortization of tangible and intangible assets and liabilities.

The unaudited pro forma condensed consolidated financial statements are provided for informational purposes only. The unaudited pro forma condensed consolidated financial statements are not necessarily and should not be assumed to be an indication of the results that would have been achieved had the transactions been completed as of the dates indicated or that may be achieved in the future. The unaudited pro forma condensed consolidated balance sheet does not include restructuring charges and other related liabilities expected to result from HCP’s integration of CRP and the Advisor as these are not presently estimable. In addition to the completion of the valuation, the impact of ongoing integration activities, the timing of completion of the transactions and other changes in CRP’s and the Advisor’s net tangible and intangible assets that occur prior to completion of the transactions could cause material differences in the information presented. Furthermore, following consummation of the transaction, HCP expects to apply its own methodologies and judgments in accounting for the assets and liabilities acquired in the transaction, which may differ from those reflected in CRP’s historical financial statements and the pro forma financial statements.

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HEALTH CARE PROPERTY INVESTORS, INC.
UNAUDITED PRO FORMA CONDENSED CONSOLIDATED BALANCE SHEET
June 30, 2006
(In thousands)