Exhibit 99.1




                            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 Annual Report of Liberty Property Trust (the "Company")
on Form 10-K for the year ended December 31, 2002 as filed with the Securities
and Exchange Commission on the date hereof (the "Report"), I, WILLIAM P.
HANKOWSKY, President and Chief Executive Officer of Liberty Property Trust,
certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906
of the Sarbanes-Oxley Act of 2002, that based on my knowledge:

         (1) The Report fully complies with the requirements of section 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.



/s/  WILLIAM P. HANKOWSKY
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William P. Hankowsky
President and Chief Executive Officer