Exhibit 5
                        SIDLEY AUSTIN BROWN & WOOD LLP

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WRITER'S DIRECT NUMBER                            WRITER'S E-MAIL ADDRESS


                                                              June 17, 2002


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

Ladies and Gentlemen:

         This opinion is furnished in connection with the Registration
Statement on Form S-3 (File No. 333-67129) filed with the Securities and
Exchange Commission (the "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 $500,000,000 (the "Debt Securities"). The
Registration Statement was declared effective by the Commission on March 11,
1999. On June 11, 2002, the Operating Partnership entered into an underwriting
agreement and related terms agreement with regard to a public offering of
$50,000,000 aggregate principal amount of its 6.00% senior unsecured notes due
2004 (the "Notes"), on terms set forth in a Prospectus Supplement dated June
11, 2002 to the Prospectus dated June 11, 2002 (together, the "Prospectus").
The Notes will be issued pursuant to an indenture dated March 26, 1999 among
the Operating Partnership, as issuer, Reckson Associates Realty Corp. (the
"Company"), as guarantor, if applicable, and The Bank of New York, as trustee
(the "Indenture").

         In connection with rendering this opinion, we have examined the
Certificate of Limited Partnership and the Amended and Restated Agreement of
Limited Partnership, as amended, of the Operating Partnership and the Articles
of Incorporation and the Bylaws, as amended, of the Company; records of
corporate proceedings of the Company; the Registration Statement; the
Indenture; the form of Notes; the Prospectus; and such other certificates,
receipts, records and documents as we considered necessary for the purposes of
this opinion.

         Based upon the foregoing, we are of the opinion that the Notes have
been duly authorized by all necessary partnership action of the Operating
Partnership, and when the Notes have been duly executed, authenticated and
delivered against consideration therefor as contemplated in the Prospectus,
the Notes will constitute valid and legally binding obligations of the
Operating Partnership and registered holders of the Notes will be entitled to
the benefits of the Indenture;



provided, however, that the foregoing opinion is subject, as to enforcement,
to bankruptcy, insolvency, reorganization, moratorium or other similar laws
relating to or affecting the enforcement of creditors' rights generally, and
to general principles of equity (regardless of whether enforcement is
considered in a proceeding in equity or at law).

         We are attorneys admitted to practice in the State of New York. We
express no opinion concerning the laws of any jurisdiction other than the
federal laws of the United States of America, the Revised Uniform Limited
Partnership Act of the State of Delaware and the laws of the State of New
York.

         We hereby consent to the filing with the Commission of this opinion
in a Current Report on Form 8-K.

                                       Very truly yours,

                                       /s/ Sidley Austin Brown & Wood LLP