<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               -------------------

                                    Form S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               ------------------

                     Washington Real Estate Investment Trust
                     ---------------------------------------
             (Exact name of Registrant as specified in its charter)


<TABLE>
<CAPTION>
<S>                                                                        <C>
                   Maryland                                                53-0261100
---------------------------------------------                          --------------------
(State or other jurisdiction                                           I.R.S. Employer
of incorporation or organization)                                      Identification No.



6110 Executive Boulevard, Suite 800                                    Larry E. Finger
Rockville, Maryland 20852                                              Senior Vice President
(301) 984-9400                                                         6110 Executive Boulevard, Suite 800
---------------------------------------------                          Rockville, Maryland 20852
(Address and telephone number of Registrant's                          (301) 984-9400
 principal executive offices)                                          -----------------------------
                                                                       (Name, address and telephone
                                                                       number of agent for service)
</TABLE>

                             2001 Stock Option Plan
                            (Full Title of the Plan)

                              --------------------

      The Commission is requested to send copies of all communications to:
                             Jeffrey E. Jordan, Esq.
                     Arent Fox Kintner Plotkin & Kahn, PLLC
                          1050 Connecticut Avenue, N.W.
                             Washington, D.C. 20036



                         CALCULATION OF REGISTRATION FEE
<TABLE>
<CAPTION>
=========================== ================= =============================== ================================ ===================
Title of securities to be   Amount to be      Proposed maximum offering       Proposed maximum aggregate       Amount of
registered                  registered        price per share(1)              offering price(1)                registration fee
--------------------------- ----------------- ------------------------------- -------------------------------- -------------------
<S>                                <C>                                 <C>                         <C>                  <C>
Shares of Beneficial               1,750,000                           $24.71                      $43,242,500          $10,810.63
Interest, $.01 par value

=========================== ================= =============================== ================================ ===================
</TABLE>

(1) Pursuant to Rule 457(h)(1), based on the average of the high and low prices
reported in the consolidated reporting system as of August 16, 2001, which is
within five business days prior to the date of the filing of this Registration
Statement.

<PAGE>



                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

Item 1.  Plan Information*

Item 2.  Registrant Information and Employee Plan Annual Information*

*        Information required by Part I to be contained in a Section 10(a)
         prospectus is omitted from the Registration Statement in accordance
         with Rule 428 under the Securities Act of 1933 (the "Securities Act")
         and the Note to Part I of Form S-8.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference

         The following documents previously filed by the Registrant with the
Securities and Exchange Commission (the "Commission") are incorporated by
reference in this Registration Statement:

         1. The Registrant's Annual Report on Form 10-K for the fiscal year
ended December 31, 2000.

         2  The Registrant's Quarterly Reports on Form 10-Q for the periods
ended March 31, 2001 and June 30, 2001.

         3  The Registrant's Current Report on Form 8-K dated February 28, 2001.

         4. The Registrant's Current Report on Form 8-K dated April 23, 2001.

         5. The Registrant's Current Report on Form 8-K dated July 19, 2001.

         6. All other reports filed pursuant to Section 13(a) or 15(d) of the
Securities Exchange Act of 1934 (the "Exchange Act") since the end of the fiscal
year ended December 31, 2000.

         7. Registrant's Form 8-A Registration Statement filed pursuant to
Section 12 of the Exchange Act, containing a description of the Registrant's
shares of beneficial interest ("Shares"), including any amendment or report
filed for the purpose of updating such description.

         In addition, all documents subsequently filed by the Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the
filing of a post-effective amendment which indicates that all securities offered
have been sold or which deregisters all securities then remaining unsold, shall
be deemed to be incorporated by reference in this Registration Statement and to
be a part hereof from the date of filing of such documents.

Item 4.  Description of Securities.

         Not Applicable.

Item 5.  Interests of Named Experts and Counsel

         David M. Osnos, a trustee of the Registrant, is a member in the firm of
Arent Fox Kintner Plotkin & Kahn, PLLC. He beneficially owns 10,100 of the
Registrant's Shares.

Item 6.  Indemnification of Directors and Officers


<PAGE>


         The Registrant's declaration of trust dated April 5, 1996 provides that
no trustee or officer of the Registrant will be personally liable, in tort,
contract or otherwise, in connection with the Registrant's property or the
affairs of the Registrant, or on account of his own acts or omissions to the
Registrant, or to any shareholder, trustee, officer or agent of the Registrant
except (1) to the extent that it is proved that the trustee or officer actually
received an improper benefit or profit in money, property, or services, in which
case the liability will not exceed the amount of the benefit or profit in money,
property, or services actually received; or (2) to the extent that a judgment or
other final adjudication adverse to the trustee or officer is entered in a
proceeding based on a finding in the proceeding that the trustee's or officer's
action or failure to act was the result of active and deliberate dishonesty and
was material to the cause of action adjudicated in the proceeding. All persons
must look solely to the Registrant's property for satisfaction of claims of any
nature in connection with the affairs of the Registrant.

         The Registrant's declaration of trust further provides for the
indemnification of the Registrant's trustees and officers to the fullest extent
permitted by Section 2-418 of the Maryland General Corporation Law.

Item 7.  Exemption from Registration Claimed

         Not applicable.

Item 8.  Exhibits

         See Exhibit Index on page 6.

Item 9.  Undertakings

         (a)      The Registrant hereby undertakes:

                  (1) To file, during any period in which offers or sales are
         being made of the securities registered hereby, a post-effective
         amendment to this Registrant Statement;

                           (i)  To include any prospectus required by Section
                  10(a)(3) of the Securities Act;

                           (ii) To reflect in the prospectus any facts or events
                  arising after the effective date of the Registration Statement
                  (or the most recent post-effective amendment thereof) which,
                  individually or in the aggregate, represent a fundamental
                  change in the information set forth in this Registration
                  Statement;

                           (iii) To include any material information with
                  respect to the plan of distribution not previously disclosed
                  in this Registration Statement or any material change to such
                  information in this Registration Statement;

provided, however, that the undertakings set forth in paragraphs (1)(i) and
--------- -------
(1)(ii) above do not apply if the information required to be included in a
post-effective amendment by those paragraphs is contained in periodic reports
filed by the Registrant pursuant to Section 13 or Section 15(d) of the Exchange
Act that are incorporated by reference in this Registration Statement.

                  (2) That, for the purpose of determining any liability under
         the Securities Act, each such post-effective amendment shall be deemed
         to be a new Registration Statement relating to the securities offered
         therein, and the offering of such securities at that time shall be
         deemed to be the initial bona fide offering thereof.

                  (3) To remove from registration by means of a post-effective
         amendment any of the securities being registered which remain unsold at
         the termination of the offering.



                                       - 2 -

<PAGE>


         (b) The Registrant hereby further undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act that is incorporated by reference in the Registration Statement
shall be deemed to be a new Registration Statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof.

         (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant, unless in the opinion of its counsel the matter has
been settled by controlling precedent, will submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.




                                       - 3 -

<PAGE>

                                   SIGNATURES
                                   ----------

         Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Rockville, State of Maryland, on the 21st day of
August, 2001.

                               WASHINGTON REAL ESTATE INVESTMENT TRUST

                                 By:  /s/ Edmund B. Cronin, Jr.
                                      -----------------------------------------
                                      President and Chief
                                      Executive Officer



                                       - 4 -

<PAGE>

                                POWER OF ATTORNEY
                                -----------------

         KNOW ALL MEN BY THESE PRESENTS that each person whose signature appears
below constitutes and appoints Edmund B. Cronin, Jr. and Larry E. Finger, and
each of them his true and lawful attorney-in-fact and agent with power of
substitution and resubstitution, for him, and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post effective
amendments) to this Registration Statement on Form S-8, and to file the same,
with all exhibits thereto, and all documents in connection therewith, with the
Commission, granting unto said attorney-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done to comply with the provisions of the
Securities Act and all requirements of the Commission, hereby ratifying and
confirming all that said attorney-in-fact or any of them, or their or his or her
substitutes, may lawfully do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities and
on the date indicated:


<TABLE>
<CAPTION>

Signatures                                       Title                                  Date
----------                                       -----                                  ----

<S>                                         <C>                                     <C>
/s/ Edmund B. Cronin, Jr                    Trustee, Chairman and                   August 21, 2001
-------------------------------------       Chief Executive
Edmund B. Cronin, Jr                        Officer (Principal
                                            Executive Officer


/s/ John M. Derrick                         Trustee                                 August 21, 2001
-------------------------------------
John M. Derrick

/s/ Larry E. Finger                         Senior Vice President and               August 21, 2001
-------------------------------------       Chief Financial Officer
Larry E. Finger                             (Principal Financial
                                            Officer)


/s/ Laura Franklin                          Managing Director,                      August 21, 2001
-------------------------------------       Accounting and
Laura Franklin                              Administration (Principal
                                            Accounting Officer)


/s/ Clifford M. Kendall                     Trustee                                 August 21, 2001
-------------------------------------
Clifford M. Kendall

/s/ John P. McDaniel                        Trustee                                 August 21, 2001
-------------------------------------
John P. McDaniel

/s/ Charles T. Nason                        Trustee                                 August 21, 2001
-------------------------------------
Charles T. Nason

/s/ David M. Osnos                          Trustee                                 August 21, 2001
-------------------------------------
David M. Osnos

/s/ Susan J. Williams                       Trustee                                 August 21, 2001
-------------------------------------
Susan J. Williams
</TABLE>




                                       - 5 -

<PAGE>


                                  EXHIBIT INDEX
                                  -------------






Exhibit
-------


5.   Opinion of Arent Fox Kintner Plotkin & Kahn
     re: validity of securities registered

23.  Consents of experts and counsel

         (a)      Consent of Arthur Andersen, LLP
                  Independent Public Accountants

         (b)      Consent of Arent Fox Kintner
                  Plotkin & Kahn (counsel): included
                  in exhibit 5

24.  Power of Attorney: included on signature page.





                                       - 6 -
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{"company-data": {"conformed-name": "WASHINGTON REAL ESTATE INVESTMENT TRUST", "cik": "0000104894", "assigned-sic": "6798", "irs-number": "530261100", "state-of-incorporation": "MD", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-68016", "film-number": "1720004"}, "business-address": {"street1": "6110 EXECUTIVE BOULEVARD", "street2": "SUITE 800", "city": "ROCKVILLE", "state": "MD", "zip": "20852", "phone": "3019295900"}, "mail-address": {"street1": "6110 EXECUTIVE BOULEVARD", "street2": "SUITE 800", "city": "ROCKVILLE", "state": "MD", "zip": "20852"}}
SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               -------------------

                                    Form S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               ------------------

                     Washington Real Estate Investment Trust
                     ---------------------------------------
             (Exact name of Registrant as specified in its charter)
Maryland                                                53-0261100
---------------------------------------------                          --------------------
(State or other jurisdiction                                           I.R.S. Employer
of incorporation or organization)                                      Identification No.

6110 Executive Boulevard, Suite 800                                    Larry E. Finger
Rockville, Maryland 20852                                              Senior Vice President
(301) 984-9400                                                         6110 Executive Boulevard, Suite 800
---------------------------------------------                          Rockville, Maryland 20852
(Address and telephone number of Registrant's                          (301) 984-9400
 principal executive offices)                                          -----------------------------
                                                                       (Name, address and telephone
                                                                       number of agent for service)
2001 Stock Option Plan
                            (Full Title of the Plan)

                              --------------------

      The Commission is requested to send copies of all communications to:
                             Jeffrey E. Jordan, Esq.
                     Arent Fox Kintner Plotkin & Kahn, PLLC
                          1050 Connecticut Avenue, N.W.
                             Washington, D.C. 20036

                         CALCULATION OF REGISTRATION FEE
=========================== ================= =============================== ================================ ===================
Title of securities to be   Amount to be      Proposed maximum offering       Proposed maximum aggregate       Amount of
registered                  registered        price per share(1)              offering price(1)                registration fee
--------------------------- ----------------- ------------------------------- -------------------------------- -------------------
Shares of Beneficial               1,750,000                           $24.71                      $43,242,500          $10,810.63
Interest, $.01 par value

=========================== ================= =============================== ================================ ===================
(1) Pursuant to Rule 457(h)(1), based on the average of the high and low prices
reported in the consolidated reporting system as of August 16, 2001, which is
within five business days prior to the date of the filing of this Registration
Statement.
PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

Item 1.  Plan Information*

Item 2.  Registrant Information and Employee Plan Annual Information*

*        Information required by Part I to be contained in a Section 10(a)
         prospectus is omitted from the Registration Statement in accordance
         with Rule 428 under the Securities Act of 1933 (the "Securities Act")
         and the Note to Part I of Form S-8.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3.  Incorporation of Documents by Reference

         The following documents previously filed by the Registrant with the
Securities and Exchange Commission (the "Commission") are incorporated by
reference in this Registration Statement:

         1. The Registrant's Annual Report on Form 10-K for the fiscal year
ended December 31, 2000.

         2  The Registrant's Quarterly Reports on Form 10-Q for the periods
ended March 31, 2001 and June 30, 2001.

         3  The Registrant's Current Report on Form 8-K dated February 28, 2001.

         4. The Registrant's Current Report on Form 8-K dated April 23, 2001.

         5. The Registrant's Current Report on Form 8-K dated July 19, 2001.

         6. All other reports filed pursuant to Section 13(a) or 15(d) of the
Securities Exchange Act of 1934 (the "Exchange Act") since the end of the fiscal
year ended December 31, 2000.

         7. Registrant's Form 8-A Registration Statement filed pursuant to
Section 12 of the Exchange Act, containing a description of the Registrant's
shares of beneficial interest ("Shares"), including any amendment or report
filed for the purpose of updating such description.

         In addition, all documents subsequently filed by the Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the
filing of a post-effective amendment which indicates that all securities offered
have been sold or which deregisters all securities then remaining unsold, shall
be deemed to be incorporated by reference in this Registration Statement and to
be a part hereof from the date of filing of such documents.

Item 4.  Description of Securities.

         Not Applicable.

Item 5.  Interests of Named Experts and Counsel

         David M. Osnos, a trustee of the Registrant, is a member in the firm of
Arent Fox Kintner Plotkin & Kahn, PLLC. He beneficially owns 10,100 of the
Registrant's Shares.

Item 6.  Indemnification of Directors and Officers
The Registrant's declaration of trust dated April 5, 1996 provides that
no trustee or officer of the Registrant will be personally liable, in tort,
contract or otherwise, in connection with the Registrant's property or the
affairs of the Registrant, or on account of his own acts or omissions to the
Registrant, or to any shareholder, trustee, officer or agent of the Registrant
except (1) to the extent that it is proved that the trustee or officer actually
received an improper benefit or profit in money, property, or services, in which
case the liability will not exceed the amount of the benefit or profit in money,
property, or services actually received; or (2) to the extent that a judgment or
other final adjudication adverse to the trustee or officer is entered in a
proceeding based on a finding in the proceeding that the trustee's or officer's
action or failure to act was the result of active and deliberate dishonesty and
was material to the cause of action adjudicated in the proceeding. All persons
must look solely to the Registrant's property for satisfaction of claims of any
nature in connection with the affairs of the Registrant.

         The Registrant's declaration of trust further provides for the
indemnification of the Registrant's trustees and officers to the fullest extent
permitted by Section 2-418 of the Maryland General Corporation Law.

Item 7.  Exemption from Registration Claimed

         Not applicable.

Item 8.  Exhibits

         See Exhibit Index on page 6.

Item 9.  Undertakings

         (a)      The Registrant hereby undertakes:

                  (1) To file, during any period in which offers or sales are
         being made of the securities registered hereby, a post-effective
         amendment to this Registrant Statement;

                           (i)  To include any prospectus required by Section
                  10(a)(3) of the Securities Act;

                           (ii) To reflect in the prospectus any facts or events
                  arising after the effective date of the Registration Statement
                  (or the most recent post-effective amendment thereof) which,
                  individually or in the aggregate, represent a fundamental
                  change in the information set forth in this Registration
                  Statement;

                           (iii) To include any material information with
                  respect to the plan of distribution not previously disclosed
                  in this Registration Statement or any material change to such
                  information in this Registration Statement;

provided, however, that the undertakings set forth in paragraphs (1)(i) and
--------- -------
(1)(ii) above do not apply if the information required to be included in a
post-effective amendment by those paragraphs is contained in periodic reports
filed by the Registrant pursuant to Section 13 or Section 15(d) of the Exchange
Act that are incorporated by reference in this Registration Statement.

                  (2) That, for the purpose of determining any liability under
         the Securities Act, each such post-effective amendment shall be deemed
         to be a new Registration Statement relating to the securities offered
         therein, and the offering of such securities at that time shall be
         deemed to be the initial bona fide offering thereof.

                  (3) To remove from registration by means of a post-effective
         amendment any of the securities being registered which remain unsold at
         the termination of the offering.

                                       - 2 -
(b) The Registrant hereby further undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act that is incorporated by reference in the Registration Statement
shall be deemed to be a new Registration Statement relating to the securities
offered therein, and the offering of such securities at that time shall be
deemed to be the initial bona fide offering thereof.

         (c) Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the Registrant pursuant to the foregoing provisions, or otherwise, the
Registrant has been advised that in the opinion of the Commission such
indemnification is against public policy as expressed in the Securities Act and
is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than the payment by the Registrant of expenses
incurred or paid by a director, officer or controlling person of the Registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the Registrant, unless in the opinion of its counsel the matter has
been settled by controlling precedent, will submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against public
policy as expressed in the Securities Act and will be governed by the final
adjudication of such issue.

                                       - 3 -
SIGNATURES
                                   ----------

         Pursuant to the requirements of the Securities Act, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Rockville, State of Maryland, on the 21st day of
August, 2001.

                               WASHINGTON REAL ESTATE INVESTMENT TRUST

                                 By:  /s/ Edmund B. Cronin, Jr.
                                      -----------------------------------------
                                      President and Chief
                                      Executive Officer

                                       - 4 -
POWER OF ATTORNEY
                                -----------------

         KNOW ALL MEN BY THESE PRESENTS that each person whose signature appears
below constitutes and appoints Edmund B. Cronin, Jr. and Larry E. Finger, and
each of them his true and lawful attorney-in-fact and agent with power of
substitution and resubstitution, for him, and in his name, place and stead, in
any and all capacities, to sign any and all amendments (including post effective
amendments) to this Registration Statement on Form S-8, and to file the same,
with all exhibits thereto, and all documents in connection therewith, with the
Commission, granting unto said attorney-in-fact and agents, and each of them,
full power and authority to do and perform each and every act and thing
requisite and necessary to be done to comply with the provisions of the
Securities Act and all requirements of the Commission, hereby ratifying and
confirming all that said attorney-in-fact or any of them, or their or his or her
substitutes, may lawfully do or cause to be done by virtue hereof.

         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed below by the following persons in the capacities and
on the date indicated:
Signatures                                       Title                                  Date
----------                                       -----                                  ----
/s/ Edmund B. Cronin, Jr                    Trustee, Chairman and                   August 21, 2001
-------------------------------------       Chief Executive
Edmund B. Cronin, Jr                        Officer (Principal
                                            Executive Officer

/s/ John M. Derrick                         Trustee                                 August 21, 2001
-------------------------------------
John M. Derrick

/s/ Larry E. Finger                         Senior Vice President and               August 21, 2001
-------------------------------------       Chief Financial Officer
Larry E. Finger                             (Principal Financial
                                            Officer)

/s/ Laura Franklin                          Managing Director,                      August 21, 2001
-------------------------------------       Accounting and
Laura Franklin                              Administration (Principal
                                            Accounting Officer)

/s/ Clifford M. Kendall                     Trustee                                 August 21, 2001
-------------------------------------
Clifford M. Kendall

/s/ John P. McDaniel                        Trustee                                 August 21, 2001
-------------------------------------
John P. McDaniel

/s/ Charles T. Nason                        Trustee                                 August 21, 2001
-------------------------------------
Charles T. Nason

/s/ David M. Osnos                          Trustee                                 August 21, 2001
-------------------------------------
David M. Osnos

/s/ Susan J. Williams                       Trustee                                 August 21, 2001
-------------------------------------
Susan J. Williams
- 5 -
EXHIBIT INDEX
                                  -------------

Exhibit
-------

5.   Opinion of Arent Fox Kintner Plotkin & Kahn
     re: validity of securities registered

23.  Consents of experts and counsel

         (a)      Consent of Arthur Andersen, LLP
                  Independent Public Accountants

         (b)      Consent of Arent Fox Kintner
                  Plotkin & Kahn (counsel): included
                  in exhibit 5

24.  Power of Attorney: included on signature page.

                                       - 6 -