EXHIBIT 99.1 CORPORATE OFFICE PROPERTIES TRUST CERTIFICATION BY THE CHIEF EXECUTIVE OFFICER RELATING TO A PERIODIC REPORT CONTAINING FINANCIAL STATEMENTS - -------------------------------------------------------------------------------- I, Clay W. Hamlin, III, Chief Executive Officer of Corporate Office Properties Trust, a Maryland real estate investment trust (the "Company"), hereby certify that: (1) The Company's periodic report on Form 10-Q for the period ended June 30, 2002 (the "Form 10-Q") fully complies with the requirements of Section 13(a) of the Securities Exchange Act of 1934, as amended; and (2) The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Company. * * * /s/ Clay W. Hamlin, III - --------------------------------- Clay W. Hamlin, III Chief Executive Officer Date: August 13, 2002 ---------------------------