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                                                                     EXHIBIT 5.1


                     [HOGAN & HARTSON L.L.P. LETTERHEAD]









                                             May 29, 1998



Equity Office Properties Trust
EOP Operating Limited Partnership
Two North Riverside Plaza
Suite 2200
Chicago, Illinois  60606

Dear Ladies and Gentlemen:

     We are acting as counsel to Equity Office Properties Trust, a Maryland
real estate investment trust (the "COMPANY"), and EOP Operating Limited
Partnership, a Delaware limited partnership (the "OPERATING PARTNERSHIP"), in
connection with their Post-Effective Amendment No. 2 on Form S-11 to their
registration statement on Form S-4 (Reg. No. 333-40401), as amended (the
"REGISTRATION STATEMENT"), filed with the Securities and Exchange Commission
relating to the proposed public offering of up to 8,413,308 of the Company's
common shares of beneficial interest, par value $.01 per share, all of which
shares (the "SHARES") are to be issued by the Company from time to time as set
forth in the prospectus which forms a part of the Registration Statement.  This
opinion letter is furnished to you at your request to enable you to fulfill the
requirements of Item 601(b)(5) of Regulation S-K, 17 C.F.R. Section
229.601(b)(5), in connection with the Registration Statement.

     We assume that the issuance of the Shares to be offered from time to time
will be duly authorized by proper action of the Board of Trustees of the
Company consistent with the description in the Registration Statement (each, a
"BOARD ACTION") and in accordance with the Company's Articles of Amendment and
Restatement of Declaration of Trust (the "DECLARATION OF TRUST") and applicable
Maryland law.




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EOP Operating Limited Partnership
May 29, 1998
Page 2




     For purposes of the opinions expressed in this letter, we have examined
copies of the following documents:

            1.   An executed copy of the Registration Statement.

            2.   The Certificate of Limited Partnership of the
                 Operating Partnership, as certified by the Secretary of State
                 of the State of Delaware on April 21, 1998, and by the
                 Secretary of the Company, as managing general partner of the
                 Operating Partnership, on the date hereof as then being
                 complete, accurate and in effect.

            3.   The Agreement of Limited Partnership of the
                 Operating Partnership, as certified by the Secretary of the
                 Company, as managing general partner of the Operating
                 Partnership, on the date hereof as then being complete,
                 accurate and in effect.

            4.   The Declaration of Trust, as certified by the
                 Maryland State Department of Assessments and Taxation on April
                 22, 1998, and by the Secretary of the Company on the date
                 hereof as then being complete, accurate and in effect.

            5.   The Bylaws of the Company, as certified by the
                 Secretary of the Company on the date hereof as then being
                 complete, accurate and in effect.

            6.   Certain resolutions of the Board of Trustees of
                 the Company adopted on September 14, 1997, as certified by the
                 Secretary of the Company on the date hereof as then being
                 complete, accurate and in effect, relating to the issuance and
                 sale of the Shares and arrangements in connection therewith.

     In our examination of the aforesaid documents, we have assumed the
genuineness of all signatures, the legal capacity of natural persons, the
authenticity, accuracy and completeness of all documents submitted to us, and
the conformity with the original documents of all documents submitted to us as
certified, telecopied, photostatic, or reproduced copies.  This opinion letter
is given, and all statements herein are made, in the context of the foregoing.




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EOP Operating Limited Partnership
May 29, 1998
Page 3




     This opinion letter is based as to matters of law solely on the Delaware
Revised Uniform Limited Partnership Act, as amended, Title 8 of the
Corporations and Associations Article of the Annotated Code of Maryland and
Maryland contract law.  We express no opinion herein as to any other laws,
statutes, ordinances, rules or regulations.

     Based upon, subject to and limited by the foregoing, we are of the opinion
that, as of the date hereof, when the Registration Statement has become
effective under the Securities Act of 1933, as amended, upon due authorization
by Board Action of an issuance of Shares, and upon issuance and delivery of
such Shares against payment therefor in accordance with the terms of such Board
Action, and as contemplated by the Registration Statement, such Shares will be
validly issued, fully paid and non-assessable.

     We assume no obligation to advise you of any changes in the foregoing
subsequent to the delivery of this opinion letter.  This opinion letter has
been prepared solely for your use in connection with the filing of the
Registration Statement on the date of this opinion letter and should not be
quoted in whole or in part or otherwise be referred to, nor filed with or
furnished to any governmental agency or other person or entity, without the
prior written consent of this firm.

     We hereby consent to the filing of this opinion letter as Exhibit 5.1 to
the Registration Statement and to the reference to this firm under the caption
"Legal Matters" in the prospectus constituting a part of the Registration
Statement.  In giving this consent, we do not thereby admit that we are an
"expert" within the meaning of the Securities Act of 1933, as amended.

                                           Very truly yours,



                                           HOGAN & HARTSON L.L.P.