Corporate Office Properties Trust Signs 131,451 Square Foot Lease at Columbia Gateway Business Park

Corporate Office Properties Trust (COPT) (NYSE:OFC) announced today the execution of a long term lease with Integral Systems, Inc. (NASDAQ:ISYS) for the entire five-story, Class A office building consisting of 131,451 square feet at Columbia Gateway Business Park. The building, located at 6721 Columbia Gateway Drive, in Columbia, Maryland, has an anticipated completion date of first quarter 2009. Integral Systems is a leading provider of satellite ground systems and has supported more than 205 different satellite missions for communications, science, meteorological, and earth resource applications. Integral Systems was the first company to offer an integrated suite of COTS (Commercial-Off-the-Shelf) software products for satellite command and control: the EPOCH IPS (Integrated Product Suite) product line. EPOCH IPS has become the world market leader in commercial applications with successful installations on five continents. This building will become the new headquarters for Integral Systems, with an anticipated occupancy date of February 2009. "We are extremely pleased, in this current economic environment, to announce this major lease with a new tenant in Columbia Gateway Business Park,” stated Randall M. Griffin, President and Chief Executive Officer for Corporate Office Properties Trust. "This is a result of our strong tenant relationships with the government and defense information technology sectors and a testament to the strength of our team, our quality product and level of customer service. Integral is a tenant in our Colorado Springs portfolio and we look forward to growing with them in this new location,” he added. Company Information Corporate Office Properties Trust (COPT) (NYSE:OFC) is a specialty office real estate investment trust (REIT) that focuses on strategic customer relationships and specialized tenant requirements in the U.S. Government, Defense Information Technology and Data sectors. The Company acquires, develops, manages and leases properties which are typically concentrated in large office parks primarily located adjacent to government demand drivers and/or in growth corridors. As of March 31, 2008, the Company owned 248 office and data properties totaling 18.7 million rentable square feet, which includes 18 properties totaling 806,000 square feet held through joint ventures. The Company’s portfolio primarily consists of technically sophisticated buildings in visually appealing settings that are environmentally sensitive, sustainable and meet unique customer requirements. More information on COPT can be found at www.copt.com. Forward-Looking Information This press release may contain "forward-looking” statements, as defined in Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, that are based on the Company’s current expectations, estimates and projections about future events and financial trends affecting the Company. Forward-looking statements can be identified by the use of words such as "may”, "will”, "should”, "expect”, "estimate” or other comparable terminology. Forward-looking statements are inherently subject to risks and uncertainties, many of which the Company cannot predict with accuracy and some of which the Company might not even anticipate. Accordingly, the Company can give no assurance that these expectations, estimates and projections will be achieved. Future events and actual results may differ materially from those discussed in the forward-looking statements. Important factors that may affect these expectations, estimates, and projections include, but are not limited to: the Company’s ability to borrow on favorable terms; general economic and business conditions, which will, among other things, affect office property demand and rents, tenant creditworthiness, interest rates and financing availability; adverse changes in the real estate markets including, among other things, increased competition with other companies; risk of real estate acquisition and development, including, among other things, risks that development projects may not be completed on schedule, that tenants may not take occupancy or pay rent or that development or operating costs may be greater than anticipated; risks of investing through joint venture structures, including risks that the Company’s joint venture partners may not fulfill their financial obligations as investors or may take actions that are inconsistent with the Company’s objectives; our ability to satisfy and operate effectively under federal income tax rules relating to real estate investment trusts and partnerships; governmental actions and initiatives; and environmental requirements. The Company undertakes no obligation to update or supplement any forward-looking statements. For further information, please refer to the Company’s filings with the Securities and Exchange Commission, particularly the section entitled "Risk Factors” in Item 1 of the Company’s Annual Report on Form 10-K for the year ended December 31, 2007.