SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported) May 31, 2006

WASHINGTON REAL ESTATE INVESTMENT TRUST

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code (301) 984-9400

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

The response set forth below under Item 8.01 is incorporated by reference herein.

On May 31, 2006, Washington Real Estate Investment Trust (“WRIT”) entered into an Underwriting Agreement (the “Shares Underwriting Agreement”) with Credit Suisse Securities (USA) LLC, A.G. Edwards & Sons, Inc., Robert W. Baird & Co., Incorporated and Raymond James & Associates, Inc. (the “Equity Underwriters”), in connection with the offer and sale of 2,600,000 of WRIT’s common shares of beneficial interest (the “Shares”). In addition to the Shares, WRIT granted the Equity Underwriters an over-allotment option to purchase up to an additional 390,000 shares. On June 5, 2006, the Equity Underwriters exercised the option to purchase 145,000 shares.

On June 1, 2006, WRIT entered into an Underwriting Agreement (together with the Shares Underwriting Agreement, the “Underwriting Agreements”) with Credit Suisse Securities (USA) LLC, Wells Fargo Securities, LLC and J.P. Morgan Securities Inc. (together with the Equity Underwriters, the “Underwriters”), in connection with the offer and sale of $100,000,000 aggregate principal amount of WRIT’s 5.95% senior notes due June 15, 2011 (the “Notes”).

WRIT and the Underwriters intend to consummate the sale and purchase of the Shares and the Notes pursuant to the Underwriting Agreements on June 6, 2006.

The Shares are described in WRIT’s prospectus supplement dated May 31, 2006 and the Notes are described in WRIT’s prospectus supplement dated June 1, 2006 (collectively, the “Prospectus Supplements”) and both supplement WRIT’s prospectus filed with the Securities and Exchange Commission (the “SEC”) pursuant to a Registration Statement on Form S-3 (File No. 333-114410), filed with the SEC on April 12, 2004, and declared effective on April 29, 2004 (the “Registration Statement”). The Prospectus Supplements were filed with the SEC on June 1, 2006 for the Shares and June 2, 2006 for the Notes, both pursuant to Rule 424(b)(5) under the Securities Act of 1933, as amended.

In connection with the offering of the Shares and the Notes, WRIT is filing certain exhibits as part of this Form 8-K that are incorporated by reference in their entirety in the Registration Statement.

(c)Exhibits

The following exhibits are filed with this report on Form 8-K:

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

June 5, 2006

Exhibit Index