Exhibit 5



                        SIDLEY AUSTIN BROWN & WOOD LLP

 BEIJING                     787 SEVENTH AVENUE                   LOS ANGELES
  ----                    NEW YORK, NEW YORK 10019                    ----
BRUSSELS                  TELEPHONE 212 839 5300                    NEW YORK
  ----                     FACSIMILE 212 839 5599                     ----
 CHICAGO                       www.sidley.com                    SAN FRANCISCO
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 DALLAS                        FOUNDED 1866                         SHANGHAI
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 GENEVA                                                            SINGAPORE
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HONG KONG                                                             TOKYO
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 LONDON                                                         WASHINGTON, D.C.





                                                May 28, 2004

Reckson Associates Realty Corp.
Reckson Operating Partnership, L.P.
225 Broadhollow Road
Melville, New York  11747

Ladies and Gentlemen:

      This opinion is furnished in connection with the registration statement
on Form S-3 (the "Registration Statement") filed with the Securities and
Exchange Commission under the Securities Act of 1933, as amended (the
"Securities Act"), relating to the registration of debt securities of Reckson
Operating Partnership, L.P., a Delaware limited partnership (the "Operating
Partnership"), in an aggregate initial public offering price not to exceed
$750,000,000 (the "Debt Securities"). The Debt Securities may be fully and
unconditionally guaranteed (the "Guarantees") under certain circumstances by
Reckson Associates Realty Corp., a Maryland corporation (the "Company"). The
Registration Statement provides that the Debt Securities may be issued in one
or more series, in amounts, at prices and on terms to be set forth in one or
more prospectus supplements to the prospectus contained in the Registration
Statement (collectively, the "Prospectus") and, if issued, will be issued
under an indenture, dated March 26, 1999, among the Operating Partnership, the
Company and The Bank of New York, as trustee, incorporated by reference in the
Registration Statement (the "Indenture").

      In arriving at the opinion expressed below, we have examined such
documents and records as we deemed appropriate, including the following: the
Certificate of Limited Partnership and the Amended and Restated Agreement of
Limited Partnership, as amended, of the Operating Partnership and the Amended
and Restated Articles of Incorporation and the Amended and Restated Bylaws, as
amended, of the Company; records of corporate proceedings of the Company; the
Registration Statement; and such other certificates, receipts, records and
documents as we considered necessary for the purposes of this opinion.

      Based upon the foregoing and subject to the limitations, qualifications,
and exceptions set forth herein, we are of the opinion that the Debt
Securities have been duly authorized by all necessary partnership action of
the Operating Partnership and the Guarantees have been duly authorized by all
necessary corporate action of the Company, and when (i) the applicable
provisions of the Securities Act and such state "blue sky" or securities laws
as may be applicable





have been complied with, and (ii) the final terms of the Debt Securities and,
if applicable, the Guarantees have been duly established and approved and have
been duly executed, authenticated (in the case of the Debt Securities) and
delivered against consideration therefor as contemplated in the Registration
Statement, such Debt Securities and Guarantees will constitute valid and
legally binding obligations of the Operating Partnership and the Company,
respectively, and registered holders of such Debt Securities will be entitled
to the benefits of the Indenture; provided, however, that the foregoing
opinion is subject, as to enforcement against the Operating Partnership, to
(i) bankruptcy, insolvency, reorganization, moratorium or other similar laws
relating to or affecting the enforcement of creditors' rights generally, (ii)
general principles of equity (regardless of whether enforcement is considered
in a proceeding in equity or at law) and (iii) provisions of law that require
a judgment for money damages rendered by a court in the United States of
America to be expressed only in U.S. dollars.

      We are members of the Bar of the State of New York and, accordingly we
express no opinion as to the laws of any jurisdiction other than the laws of
the State of New York, the federal securities laws of the United States of
America, the Revised Uniform Partnership Act of the State of Delaware and the
Maryland General Corporation Law.

      We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and the reference to our firm in the Prospectus under
the caption "Legal Matters."

                                          Very truly yours,


                                          /S/ Sidley Austin Brown & Wood LLP


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