UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 14A
SCHEDULE 14A INFORMATION
Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934
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o	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
o	Definitive Proxy Statement
x	Definitive Additional Materials
o	Soliciting Material Pursuant to §240.14a-12
COMMONWEALTH REIT
(Name of Registrant as Specified In Its Charter)
(Name of Person(s) Filing Proxy Statement, if other than the Registrant)
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M30464-P07648 You are receiving this communication because you hold shares in the company named above. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet or by mail. We encourage you to access and review all of the important information contained in the proxy materials before voting. COMMONWEALTH REIT Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on May 10, 2011. COMMONWEALTH REIT TWO NEWTON PLACE 255 WASHINGTON STREET, SUITE 300 NEWTON, MA 02458 Meeting Information Meeting Type: Annual For holders as of: 2/18/2011 Date: 5/10/2011 Time: 9:30 a.m., local time Location: CommonWealth REIT Two Newton Place 255 Washington Street, Suite 100 Newton, MA 02458 See the reverse side of this notice to obtain proxy materials and voting instructions. NOTICE OF ANNUAL MEETING OF SHAREHOLDERS

M30465-P07648 Vote In Person: Shareholders of record of the company as of February 18, 2011 or their duly authorized proxies are entitled to vote in person at the meeting. At the meeting, you will need to request a ballot to vote these shares. To obtain directions for the annual meeting, please call 617-332-3990. Authorize Your Proxy By Internet: To vote now by Internet, go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow available and follow the instructions. Authorize Your Proxy By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card. Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. How to View Online: Have the information that is printed in the box marked by the arrow (located on the following page) and visit: www.proxyvote.com. If you want to receive a paper or e-mail copy of these documents, you must request one. There is no charge to you for requesting a copy. Please make your request for a copy as instructed below on or before April 26, 2011 to facilitate timely delivery. How to Request and Receive a PAPER or E-MAIL Copy for the 2011 Annual Meeting and for Shareholder Meetings in the Future: 1) BY INTERNET: www.proxyvote.com 2) BY TELEPHONE: 1-800-579-1639 3) BY E-MAIL*: sendmaterial@proxyvote.com * If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow (located on the following page) in the subject line. Before You Vote How to Access the Proxy Materials The Notice of Annual Meeting, Proxy Statement and Annual Report are available at www.proxyvote.com. XXXX XXXX XXXX XXXX XXXX XXXX Please Choose One of the Following Voting Methods XXXX XXXX XXXX How To Vote

Voting Items M30466-P07648 Our Board of Trustees Recommends You Vote "FOR" the Nominees for Trustee in Proposals 1 and 2, "FOR" Proposal 3, "THREE YEARS" in Proposal 4 and "FOR" Proposal 5. 2. To elect the nominee named in our proxy statement to our Board of Trustees as the Managing Trustee in Group I. Nominee: Barry M. Portnoy Our Board recommends you vote FOR proposal 2. 1. To elect the nominee named in our proxy statement to our Board of Trustees as the Independent Trustee in Group I. Nominee: Frederick N. Zeytoonjian Our Board recommends you vote FOR proposal 1. 3. To approve a nonbinding advisory resolution on our executive compensation. Our Board recommends you vote FOR proposal 3. 5. To ratify the appointment of Ernst & Young LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2011. Our Board recommends you vote FOR proposal 5. 4. To recommend, by nonbinding advisory vote, the frequency of shareholder nonbinding advisory votes relating to our executive compensation. Our Board recommends you vote 3 YEARS in proposal 4. 6. To consider and vote upon such other matters as may properly come before the meeting and at any adjournments or postponements thereof.

M30467-P07648