EXHIBIT 32.1

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report on Form 10-Q of Mack-Cali Realty Corporation (the “Company”) for the quarterly period ended June 30, 2007, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Mitchell E. Hersh, as President and Chief Executive Officer of the Company, and Barry Lefkowitz, as Chief Financial Officer of the Company, each hereby certifies, pursuant to 18 U.S.C. §1350, as adopted pursuant to §906 of the Sarbanes-Oxley Act of 2002, that:

(1)          The Report fully complies with the requirements of §13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)          The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date:                    August 1, 2007	By:	/s/ Mitchell E. Hersh
		Mitchell E. Hersh
		President and
		Chief Executive Officer
Date:                    August 1, 2007	By:	/s/ Barry Lefkowitz
		Barry Lefkowitz
		Executive Vice President and
		Chief Financial Officer

 

This certification accompanies each Report pursuant to §906 of the Sarbanes-Oxley Act of 2002 and shall not, except to the extent required by the Sarbanes-Oxley Act of 2002, be deemed filed by the Company for purposes of §18 of the Securities Exchange Act of 1934, as amended.

A signed original of this written statement required by §906 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.