N@N

COLUMBIA, Md.--([ BUSINESS WIRE ])--Corporate Office Properties Trust (COPT or the Company) (NYSE: OFC) has executed three leases with strategic tenants totaling 363,300 square feet of Class A office space at its Redstone Gateway project in Huntsville, AL. A strategic tenant has leased the Companyas existing office building, 1000 Redstone Gateway, in its entirety. In addition, multiple leases have been signed for 100% of two new office buildings totaling 242,200 square feet; construction of 1100 Redstone Gateway and 1200 Redstone Gateway is scheduled to commence prior to year end. The Company anticipates the tenants will occupy 1000 Redstone Gateway in mid-2013 and the 1100 and 1200 Redstone Gateway buildings by the first quarter of 2014.

"These transactions also illustrate the cooperative and growing relationship between the Garrison, the Huntsville community and COPT"

As a result of this leasing and the Companyas leasing at Riverwood in Columbia, MD (see press release dated September 10, 2012), the Companyas construction pipeline will increase from approximately 987,800 square feet at June 30, 2012 to 1.25 million square feet. Pre-leasing, which was at 25% on June 30, 2012, now approximates 58%.

aThese leases firmly establish Redstone Gateway as a desirable location from which strategic tenants can serve Redstone Arsenalas various missions,a stated Roger A. Waesche, Jr., President & Chief Executive Officer of COPT. aThese transactions also illustrate the cooperative and growing relationship between the Garrison, the Huntsville community and COPT,a he stated.

Redstone Gateway is a consolidated joint venture formed in March 2010 between COPT (85% ownership) and Jim Wilson & Associates (15% partner).

Company Information:

COPT is an office real estate investment trust (REIT) that focuses primarily on strategic customer relationships and specialized tenant requirements in the U.S. Government and Defense Information Technology sectors and Data Centers serving such sectors. The Company acquires, develops, manages and leases office and data center properties that are typically concentrated in large office parks primarily located adjacent to government demand drivers and/or in strong markets that it believes possess growth opportunities. As of June 30, 2012, COPTas consolidated portfolio consisted of 228 office properties totaling 19.8million rentable square feet. The Companyas portfolio primarily consists of technically sophisticated buildings in visually appealing settings that are environmentally sensitive, sustainable and meet unique customer requirements. COPT is an S&P MidCap 400 company and more information can be found at [ www.copt.com ].

Forward-Looking Information:

This press release may contain aforward-lookinga 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 Companyas 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 amay,a awill,a ashould,a acould,a abelieve,a aanticipate,a aexpect,a aestimate,a aplana 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:

• general economic and business conditions, which will, among other things, affect office property and data center demand and rents, tenant creditworthiness, interest rates, financing availability and property values;
• adverse changes in the real estate markets including, among other things, increased competition with other companies;
• governmental actions and initiatives, including risks associated with the impact of a government shutdown or budgetary reductions or impasses, such as a reduction in rental revenues, non-renewal of leases, and/or a curtailment of demand for additional space by strategic tenants;
• the Companyas ability to sell properties included in its Strategic Reallocation Plan;
• the Companyas ability to borrow on favorable terms;
• risks of real estate acquisition and development activities, 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 Companyas joint venture partners may not fulfill their financial obligations as investors or may take actions that are inconsistent with the Companyas objectives;
• changes in the Companyas plans or views of market economic conditions or failure to obtain development rights, any of which could result in recognition of impairment losses;
• the Companyas ability to satisfy and operate effectively under Federal income tax rules relating to real estate investment trusts and partnerships;
• the dilutive effect of issuing additional common shares; and
• environmental requirements.

The Company undertakes no obligation to update or supplement any forward-looking statements. For further information, please refer to the Companyas filings with the Securities and Exchange Commission, particularly the section entitled aRisk Factorsa in Item 1A of the Companyas Annual Report on Form 10-K for the year ended December 31, 2011.