Exhibit 99.1

THIRD QUARTER 2003
Supplemental Operating and Financial Data

This Supplemental Operating and Financial Data is not an offer to sell or solicitation to buy any securities of the Company. Any offers to sell or solicitations of the Company shall be made by means of a prospectus. The information in this Supplemental Package must be read in conjunction with, and is modified in its entirety by, the Quarterly Report on Form 10-Q (the "10-Q") filed by the Company for the same period with the Securities and Exchange Commission (the "SEC") and all of the Company's other public filings with the SEC (the "Public Filings"). In particular, the financial information contained herein is subject to and qualified by reference to the financial statements contained in the 10-Q, the footnotes thereto and the limitations set forth therein. Investors may not rely on the Supplemental Package without reference to the 10-Q and the Public Filings. Any investors' receipt of, or access to, the information contained herein is subject to this qualification.

Mack-Cali Realty Corporation
Supplemental Operating and Financial Data for the Quarter Ended September 30, 2003

INDEX

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DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS

        Certain information discussed in this literature may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and the federal securities laws, including Section 21E of the Securities Exchange Act of 1934. The Company intends such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995 and Section 21E of the Securities Exchange Act of 1934. Such forward-looking statements relate to, without limitation, the Company's future economic performance, plans and objectives for future operations and projections of revenue and other financial items. Forward-looking statements can be identified by the use of words such as "may," "will," "should," "expect," "anticipate," "estimate," "continue" or comparable terminology. Although the Company believes that the expectations reflected in such forward-looking statements are based upon reasonable assumptions at the time made, it can give no assurance that its expectations will be achieved. Forward-looking statements are inherently subject to certain risks, trends and uncertainties, many of which the Company cannot predict with accuracy and some of which the Company might not even anticipate. Future events and actual results, financial and otherwise, may differ materially from the results discussed in the forward-looking statements. Readers are cautioned not to place undue reliance on these forward-looking statements. Among the risks, trends and uncertainties are changes in the general economic conditions, including those affecting industries in which the Company's principal tenants compete; any failure of the general economy to recover timely from the current economic downturn; the extent of any tenant bankruptcies; the Company's ability to lease or re-lease space at current or anticipated rents; changes in the supply of and demand for office, office/flex and industrial/warehouse properties; changes in interest rate levels; changes in operating costs; the Company's ability to obtain adequate insurance, including coverage for terrorist acts; the availability of financing; and other risks associated with the development and acquisition of properties, including risks that the development may not be completed on schedule, that the tenants will not take occupancy or pay rent, or that development or operating costs may be greater than anticipated. For further information on factors which could impact the Company and the statements contained herein, reference should be made to the Company's filings with the Securities and Exchange Commission including Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and Annual Reports on Form 10-K. The Company assumes no obligation to update or supplement forward-looking statements that become untrue because of subsequent events.

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I. COMPANY BACKGROUND

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I. COMPANY BACKGROUND

About the Company

        Mack-Cali Realty Corporation (NYSE: CLI) is one of the largest real estate investment trusts (REITs) in the United States with a total market capitalization of $4.5 billion at September 30, 2003. Mack-Cali has been involved in all aspects of commercial real estate development, management and ownership for over 50 years and has been a publicly-traded REIT since 1994. Mack-Cali owns or has interests in 265 properties, primarily class A office and office/flex buildings, totaling approximately 28.5 million square feet, serving as home to approximately 2,100 tenants. The properties are located primarily in suburban markets of the Northeast, many with adjacent, Company-controlled developable land sites able to accommodate up to 8.3 million square feet of additional commercial space.

History

        Established over 50 years ago, in 1994 the New Jersey-based firm became a publicly-traded company listed on the New York Stock Exchange under the ticker symbol CLI. Through combinations with some of the top companies in the real estate industry—most notably New Jersey-based Mack Company and Westchester, New York-based Robert Martin Company—Mack-Cali has become one of the leading real estate companies in the country.

Strategy

        Mack-Cali's strategy is to be a significant real estate owner and operator in its core, high-barriers-to-entry markets, primarily in the Northeast.

Summary
(as of September 30, 2003)

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Board of Directors
William L. Mack, Chairman of the Board

Executive Officers

Mitchell E. Hersh, Chief Executive Officer

Timothy M. Jones, President

Barry Lefkowitz, Executive Vice President and Chief Financial Officer

Roger W. Thomas, Executive Vice President, General Counsel and Secretary

Michael A. Grossman, Executive Vice President

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Equity Research Coverage

Company Contact Information

Mack-Cali Realty Corporation
Investor Relations Department
11 Commerce Drive
Cranford, New Jersey 07016-3599

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II. FINANCIAL HIGHLIGHTS

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II. FINANCIAL HIGHLIGHTS

Quarterly Summary

        Funds from operations (FFO) available to common shareholders for the quarter ended September 30, 2003 amounted to $69.6 million, or $0.96 per share, versus $72.6 million, or $1.01 per share, for the quarter ended September 30, 2002. For the nine months ended September 30, 2003, FFO available to common shareholders amounted to $209.2 million, or $2.91 per share, versus $213.5 million, or $2.98 per share, for the same period last year.

        Net income available to common shareholders for the third quarter 2003 equaled $50.4 million, or $0.84 per share, versus $34.2 million, or $0.59 per share, for the same quarter last year, a per share increase of 42.4 percent. For the nine months ended September 30, 2003, net income available to common shareholders equaled $114.0 million, or $1.96 per share, versus $109.9 million, or $1.91 per share, for the same period last year, an increase of 2.6 percent on a per share basis.

        Total revenues for the third quarter 2003 increased 3.6 percent to $147.4 million as compared to $142.3 million for the same quarter last year. For the nine months ended September 30, 2003, total revenues amounted to $440.7 million, an increase of 3.6 percent over total revenues of $425.4 million for the same period last year.

        All per share amounts presented above are on a diluted basis; basic earnings per share is included in the financial tables on page 23.

        The Company had 58,182,631 shares of common stock, 10,000 shares of cumulative redeemable perpetual preferred stock, 7,795,498 common operating partnership units and 215,456 $1,000-face-value preferred operating partnership units outstanding as of quarter end.

        The outstanding preferred units are convertible into 6,218,066 common operating partnership units. Assuming conversion of all preferred units into common units, the Company had a total of 72,196,195 shares/common units outstanding at September 30, 2003.

        As of September 30, 2003, the Company had total indebtedness of approximately $1.6 billion, with a weighted average annual interest rate of 7.10 percent. Mack-Cali had a total market capitalization of $4.5 billion and a debt-to-undepreciated assets ratio of 38.5 percent at September 30, 2003. The Company had an interest coverage ratio of 3.4 times for the quarter ended September 30, 2003.

        The following is a summary of the Company's recent activity:

Acquisitions

        During the quarter, the Company acquired three office properties, aggregating 202,184 square feet, for approximately $24.5 million, as follows:

•

In August, the Company acquired 3 Odell Plaza, a 71,065 square-foot office/flex building in Yonkers, New York. The property, located at Mack-Cali's South Westchester Executive Park, was purchased from the Schott Corporation for approximately $6 million. Simultaneously, the Company announced that Montefiore Medical Center leased 44,590 square feet for 15 years at the property. In addition, the seller of the property, Schott Corporation, signed a 10-year lease for 16,815 square feet for its U.S. corporate headquarters at Mack-Cali's 555 Taxter Road property in Taxter Corporate Park in Elmsford, New York;



•

In September, the Company acquired 4 Sentry Parkway, a 63,930 square-foot class A office building located in the Sentry Park office campus in Blue Bell, Pennsylvania for approximately $10.2 million; and

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•

Also in September, the Company acquired 14 Commerce Drive, a 67,189 square-foot office building located in Cranford, New Jersey, for approximately $8.3 million.

Sales Activity

        On September 29, 2003, the Company sold its interest in American Financial Exchange LLC, a joint venture which developed Harborside Financial Center Plaza 10, a 577,575 square-foot class A office building 100 percent pre-leased to Charles Schwab & Co., which is located in Jersey City, New Jersey. The Company received approximately $162.1 million in net sales proceeds from the transaction, which it used primarily to repay outstanding borrowing under its revolving credit facility. The Company recognized a gain on the sale of approximately $23.1 million, which is recorded in gain on sale of investment in unconsolidated joint venture for the three and nine months ended September 30, 2003. The Company will continue to manage the property for the new owner.

        More recently in October, the Company sold Riverview Tower, a 248,153 square-foot office building located in San Antonio, Texas, for approximately $11.025 million.

Financing Activity

        In September, the Company's Board of Directors declared a cash dividend of $0.63 per common share (indicating an annual rate of $2.52 per common share) for the third quarter 2003, which was paid on October 20, 2003 to shareholders of record as of October 3, 2003. The Board of Directors also declared a cash dividend of $0.50 per depositary share, each representing 1/100^th of a share of 8 percent Series C cumulative redeemable perpetual preferred stock ($25 liquidation value per depositary share) for the period July 15, 2003 through October 14, 2003. The preferred stock dividend was paid on October 15, 2003 to shareholders of record as of October 3, 2003.

Leasing Information

        Mack-Cali's consolidated portfolio of stabilized operating properties, before the effect of adding Harborside Financial Center Plaza 5, was 92.0 percent leased at September 30, 2003, compared to 92.2 percent leased at June 30, 2003. Adding, for the first time, Plaza 5 (56.2 percent leased at quarter end previously classified as a development property in lease up) resulted in a decrease of 1.3 percent in the Company's consolidated portfolio of stabilized operating properties to 90.7 percent at September 30, 2003.

        For the quarter ended September 30, 2003, the Company executed 183 leases totaling 1,242,817 square feet, consisting of 766,848 square feet of office space, 331,587 square feet of office/flex space and 144,382 square feet of industrial/warehouse space. Of these totals, 444,398 square feet were for new leases and 798,419 square feet were for lease renewals and other tenant retention transactions.

        Highlights of the quarter's leasing transactions include:

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San Mar Laboratories, Inc., a private label manufacturer of cosmetic products, signed a 12-year 122,282 square-foot renewal at 4 Warehouse Lane in Elmsford, New York. The 195,500 square-foot industrial/warehouse property, located in the Elmsford Distribution Center, is 100 percent leased.



•

ClubCorp, Inc., an owner/operator of private golf and business clubs, signed a 12-year renewal for 88,256 square feet at 3030 LBJ Freeway in Dallas, Texas. The 367,018 square-foot class A office property is 81.6 percent leased.



•

Rock Bottom Restaurants, Inc. a national restaurant owner and operator, signed a renewal and expansion totaling 39,322 square feet at 248 Centennial Parkway in Louisville, Colorado. The

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transaction expands the tenant's existing lease by 16,326 square feet for five years. Rock Bottom Restaurants now leases 100 percent of the building.

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Citigroup Global Markets, Inc., a division of financial services provider Citigroup, Inc., renewed its lease for 26,834 square feet at 150 JFK Parkway in Short Hills, New Jersey for 10 years. The 247,476 square-foot class A office building is 98.7 percent leased.



•

Coram Alternate Site Services, a provider of home health care, leased 36,370 square feet at two office/flex buildings at Mack-Cali Commercenter in Totowa, New Jersey. The company renewed its lease for 26,125 square feet at 11 Commerce Way for five years and signed a new lease for 10,245 square feet at 20 Commerce Way for six years. Both buildings are 100 percent leased.



•

Cap Gemini Telecom Media & Networks U.S., Inc., a division of Cap Gemini Ernst & Young, renewed its lease for 23,175 square feet at 100 Walnut Avenue in Clark, New Jersey for a term of five years. The 182,555 square-foot class A office property is 100 percent leased.



•

The Artina Group, Inc., a distributor of software-compatible forms, renewed its lease for 22,141 square feet at 250 Clearbrook Road in the Cross Westchester Executive Park in Elmsford, New York for five years. The 155,000 square-foot office/flex building is 95.1 percent leased.



•

National Association of Securities Dealers, Inc. (NASD), a private-sector provider of financial regulatory services, signed a 10-year lease transaction totaling 19,832 square feet. The deal represented a 13,932 square-foot renewal and expansion of 5,900 square feet at 581 Main Street in Woodbridge, New Jersey. The 200,000 square-foot class A office property is 100 percent leased.



•

WithumSmith+Brown, a public accounting firm, signed a new 10-year lease for 19,407 square feet at 5 Vaughn Drive in Princeton, New Jersey. 5 Vaughn Drive, a 98,500 square-foot class A office property, is 98.1 percent leased.

        Also during the third quarter 2003, the Company signed a new five-year lease with Moody's Investors Service, Inc. for 43,344 square feet at Harborside Financial Center Plaza 5 in Jersey City, New Jersey. More recently, the Company signed a new lease at Plaza 5 with the Office of Thrift Supervision, a bureau of the U.S. Department of Treasury, for 20,664 square feet which brought the 980,000 square-foot class A office property to 58.3 percent leased.

Information About FFO

        Funds from operations ("FFO") is defined as net income (loss) before minority interest of unitholders, computed in accordance with generally accepted accounting principles ("GAAP"), excluding gains (or losses) from extraordinary items and sales of depreciable rental property, plus real estate-related depreciation and amortization. The Company believes that FFO is helpful to investors as one of several measures of the performance of an equity REIT. The Company further believes that by excluding the effect of depreciation and gains (or losses) from sales of properties (all of which are based on historical costs which may be of limited relevance in evaluating current performance), FFO can facilitate comparison of operating performance between equity REITs. FFO should not be considered as an alternative to net income as an indication of the Company's performance or to cash flows as a measure of liquidity. FFO presented herein is not necessarily comparable to FFO presented by other real estate companies due to the fact that not all real estate companies use the same definition. However, the Company's FFO is comparable to the FFO of real estate companies that use the current definition of the National Association of Real Estate Investment Trusts ("NAREIT"). A reconciliation of net income to FFO is included in the financial tables on page 26.

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Key Financial Data

(a)

Includes preferred units on a converted basis into common units.

(b)

Calculated based on weighted average common shares outstanding, assuming redemption of operating partnership common units into common shares.

(c)

Calculated based on shares and units included in basic per share/unit computation, plus dilutive Common Stock Equivalents (i.e. convertible preferred units, options and warrants).

(d)

Includes preferred units on a converted basis into common units and minority interests in partially-owned properties.

(e)

Funds from Operations ("FFO") is calculated in accordance with the National Association of Real Estate Investment Trusts (NAREIT) definition, as published in October 1999.

(f)

Reflects square feet leased at the Company's consolidated in-service portfolio, excluding in-service development properties in lease up (if any).

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Same Store Results and Analysis
(dollars in thousands)

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Unconsolidated Joint Ventures Summary

Breakdown of Unconsolidated Joint Ventures

(a)

Property consists of a three-story theater and retail complex.

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Unconsolidated Joint Venture Financial Information

        The following is a summary of the financial position of the unconsolidated joint ventures in which the Company had investment interests as of September 30, 2003 and December 31, 2002:

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        The following is a summary of the results of operations of the unconsolidated joint ventures for the period in which the Company had investment interests during the three months ended September 30, 2003 and 2002:

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        The following is a summary of the results of operations of the unconsolidated joint ventures for the period in which the Company had investment interests during the nine months ended September 30, 2003 and 2002: