EXHIBIT 5


                       ROSENBERG & LIEBENTRITT, P.C.
                         Two North Riverside Plaza
                                Suite 1515
                          Chicago, Illinois 60606
                          Telephone 312.466.3456
                             Fax 312.454.0335


                               November 25, 1997



ERP Operating Limited Partnership
c/o Board of Trustees
Equity Residential Properties Trust
Two North Riverside Plaza
Suite 400
Chicago, Illinois  60606

Ladies and Gentlemen:


     We are acting as counsel to ERP Operating Limited Partnership, an Illinois
limited partnership (the "Operating Partnership"), the general partner of which
is Equity Residential Properties Trust, a Maryland real estate investment trust
(the "Company") in connection with the Operating Partnership's registration
statement on Form S-3 (the "Registration Statement") previously declared
effective by the Securities and Exchange Commission relating to unsecured senior
debt securities in a maximum aggregate offering price of $500,000,000 (the
"Securities") (SEC File No. 333-12213), all of which Securities may be offered
and sold by the Operating Partnership from time to time as set forth in the
prospectus which forms a part of the Registration Statement (the "Prospectus"),
and as to be set forth in one or more supplements to the Prospectus (each, a
"Prospectus Supplement").  This opinion letter is rendered in connection with
the proposed public offering by the Operating Partnership of (i) $150,000,000
principal amount of its 6.55% Notes due November 15, 2001 and (ii) $50,000,000
principal amount of its 6.65% Notes due November 15, 2003 (collectively, the
"Notes") as described in a Prospectus Supplement dated November 20, 1997.  This
opinion letter is furnished to you at your request to enable the Operating
Partnership to continue to fulfill the requirements of Item 601(b)(5) of
Regulation S-K, 17 C.F.R. (S)229.601(b)(5), in connection with the Registration
Statement.

     For purposes of this opinion letter, we have examined copies of the
following documents:


     1.  An executed copy of the Registration Statement.

     2.  The Second Amended and Restated Declaration of Trust of the Company
         (the "Declaration of Trust"), as certified by the Secretary of the
         Company on the date hereof as then being complete, accurate and in
         effect.

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

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

     5.  Resolutions of the Board of Trustees of the Company, as the general
         partner of the Operating Partnership, adopted on September 13, 1996 and
         November 14, 1997 relating to the filing of the Registration Statement
         and related matters, and by the Pricing Committee of the Board of
         Trustees on November 20, 1997, relating to the offering of the Notes,
         each as certified by the Secretary of the Company on the date hereof as
         then being complete, accurate and in effect.

     6.  Executed copies of the Purchase Agreement, dated December 13, 1994,
         between the Operating Partnership, Merrill Lynch & Co. and Merrill
         Lynch, Pierce, Fenner & Smith Incorporated, and the Terms Agreement,
         dated November 20, 1997, between the Operating Partnership and each of
         Merrill Lynch, Pierce, Fenner & Smith Incorporated, BancAmerica
         Robertson Stephens and J.P. Morgan Securities Inc. (collectively, the
         "Underwriting Agreement").

     In our examination of the aforesaid documents, we have assumed the
genuineness of all signatures, the legal capacity of natural persons, the
accuracy and completeness of all documents submitted to us, the authenticity of
all original documents, and the conformity to authentic 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.

     We call your attention to the fact that our firm only requires lawyers to
be qualified to practice law in the State of Illinois and, in rendering the
foregoing opinions, we express no opinion with respect to any laws relevant to
this opinion other than the laws and regulations identified herein.

     Based upon, subject to and limited by the foregoing, we are of the opinion
that, as of the date hereof, following issuance of the Notes pursuant to the
terms of the Underwriting Agreement and receipt by the Operating Partnership of
the consideration for the Notes specified in the resolutions of the Company's
Board of Trustees and the Pricing Committee referred to above, the Notes will be
validly issued and legally binding obligations of the Operating Partnership
enforceable against the Operating Partnership in accordance with their terms,
subject to applicable bankruptcy, insolvency, reorganization, moratorium,
fraudulent transfer, or similar laws affecting creditors' rights generally from
time to time in effect and general principles of equity (regardless of whether
such enforceability is considered in a proceeding at law or in equity) and
except that a waiver of rights under any usury law may be unenforceable.

     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

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connection with the filing by the Operating Partnership of a Current Report on
Form 8-K on the date of this opinion letter, which Form 8-K will be incorporated
by reference into the Registration Statement. This opinion letter 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 (i) to be named in the Registration Statement, and in the
Prospectus, as attorneys who will pass upon the legality of the Securities to be
sold thereunder and (ii) to the filing of this opinion as an Exhibit to 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,

                                 ROSENBERG & LIEBENTRITT, P.C.

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