EXHIBIT 5.1



September 21, 2001

Fairfield Inn by Marriott Limited Partnership
c/o AP-Fairfield GP, LLC
7 Bulfinch Place
Boston, Massachusetts 02114



Ladies and Gentlemen:

         We have acted as counsel to Fairfield Inn by Marriott Limited
Partnership, a Delaware limited partnership (the "Partnership"), in connection
with the preparation and filing by the Partnership with the Securities and
Exchange Commission of a Registration Statement on Form S-1 (the "Registration
Statement") under the Securities Act of 1933 relating to $23,000,000 aggregate
principal amount of the Partnership's Subordinated Notes due 2007 (the "Notes")
to be issued and sold in the manner described in the Registration Statement.

         We have reviewed and examined copies of the Partnership's Limited
Partnership Agreement, and amendments thereto, the Partnership's Certificate of
Limited Partnership, the form of Notes, and such other documents, records and
matters of law as we have deemed necessary for purposes of this opinion. In such
examination, we have assumed the authenticity of all documents submitted to us
as originals and the conformity with the original documents of all documents
submitted to us as copies.

         Based on the foregoing and on such legal considerations as we deem
relevant, we are of the opinion that the Notes have been duly authorized and,
when duly executed, authenticated and delivered to and paid for by the
purchasers thereof in the manner described in the Registration Statement, will
be valid and binding obligations of the Partnership.

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


Very truly yours,

Rosenman & Colin LLP



By: /s/ Robert Fisher
   ------------------------
          a Partner