Corporate Office Properties Trust Calls Series F Cumulative Redeemable Preferred Shares for Redemption.

COLUMBIA, Md. -- Corporate Office Properties Trust (COPT) (NYSE: OFC) announced today that the Company has called for redemption all of its 1,425,000 outstanding 9.875% Series F Cumulative Redeemable Preferred Shares (the "Series F Preferred Shares") (NYSE: OFCPrF), at a price of $25.00 per Series F Preferred Share. There will be no accrued and unpaid dividends on the date of redemption (the "Series F Redemption Price").

The redemption date for the Series F Preferred Shares will be October 15, 2006 (the "Redemption Date"). From the Redemption Date forward, dividends on the Series F Preferred Shares will no longer accrue and holders of the Series F Preferred Shares will have no rights as such holders other than the right to receive the Series F Redemption Price, without interest, upon surrender of the Series F Preferred Shares.

Redemption of the Series F Preferred Shares will result in the Company recording a $2.1 million charge in the fourth quarter of 2006 as a result of its write-off of the initial offering costs associated with the issuance of the Series F Preferred Shares in accordance with the Securities and Exchange Commission's July 31, 2003 clarification on Emerging Issues Task Force Abstract, Topic No. D 42, "The Effect on the Calculation of Earnings per Share for the Redemption or Induced Conversion of Preferred Stock."

The Company anticipates that the $2.1 million charge will affect the Company's previously announced earnings estimate for the year ending December 31, 2006 by reducing earnings per share ("EPS") on a fully diluted basis by approximately $(0.05) and funds from operations ("FFO") per share on a fully diluted basis by approximately $(0.04). Please see the attached table for a reconciliation of the projected decrease in diluted EPS and diluted FFO per share.

The Notice of Redemption and related materials have already been mailed to holders of record of the Series F Preferred Shares. Wells Fargo Shareowner Services is acting as the redemption agent. Requests for additional copies of the materials should be directed to Mary Ellen Fowler, Vice President and Treasurer, at 443-285-5450.

Company Information

Corporate Office Properties Trust (COPT) is a fully integrated, self-managed real estate investment trust (REIT) that focuses on the ownership, management, leasing, acquisition and development of suburban office properties located primarily in submarkets within the Greater Washington, DC region. As of June 30, 2006, the Company owned 189 office properties totaling 15.8 million rentable square feet, which included 19 properties totaling 963,000 square feet held through joint ventures. The Company has implemented a core customer expansion strategy that is built around meeting, through acquisitions and development, the multi-location requirements of the Company's existing strategic tenants. The Company's property management services team provides comprehensive property and asset management to company owned properties and select third party clients. The Company's development and construction services team provides a wide range of development and construction management services for company owned properties, as well as land planning, design/build services, consulting, and merchant development to select third party clients. The Company's shares are traded on the New York Stock Exchange under the symbol OFC. More information on Corporate Office Properties Trust can be found on the Internet 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, 2005.

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