EXHIBIT 5
 
                                     [   ]
 
                                     [   ]
 
                                      1997
 
                                                                     750,014-058
                                                                   LA1-755741.V2
 
(213) 669-6000
 
Santa Anita Realty Enterprises, Inc.
301 West Huntington Drive, Suite 405
Arcadia, California 91007
 
Santa Anita Operating Company
285 West Huntington Drive
Arcadia, California 91007
 
    Re: Registration Statement on Form S-4
 
Dear Ladies and Gentlemen:
 
  In connection with the registration under the Securities Act of 1933, as
amended (the "Act") of up to [   ] shares of Common Stock of Santa Anita Realty
Enterprises, Inc. ("Realty"), par value $0.10 per share ("Realty Common
Stock"), and up to [   ] shares of Common Stock of Santa Anita Operating
Company ("Operating"), par value $0.10 per share ("Operating Common Stock"), to
be issued in connection with the proposed mergers of Meditrust with and into
Realty and Meditrust Acquisition Company with and into Operating (collectively,
the "Mergers"), pursuant to the Registration Statement on Form S-4 (File No.
33-   ) (the "Registration Statement"), filed with the Securities and Exchange
Commission on [   ], 1997, you have requested our opinion set forth below. Such
shares of Realty Common Stock and Operating Common Stock, which will be paired
for transfer and trading purposes, are referred to herein as "Shares."
 
  We have considered such facts and examined such questions of law as we have
considered appropriate for purposes of rendering the opinion expressed below.
 
  We are opining only as to the General Corporation Law of the State of
Delaware and we express no opinion with respect to the applicability or the
effect of any other laws or as to any matters of municipal law or of any other
local agencies within any state.
 
  Subject to the foregoing and in reliance thereon, in our opinion, upon
approval of the Mergers by the respective stockholders of Realty, Operating,
Meditrust and Meditrust Acquisition Company in accordance with the terms and
conditions set forth in the Registration Statement and the filing of
Certificates of Merger with the Secretary of State of the State of Delaware and
Certificates of Termination with the Secretary of State of the Commonwealth of
Massachusetts and the issuance and delivery of the shares pursuant to the
Mergers, the Shares will be duly authorized, validly issued, fully paid and
non-assessable.
 
  We consent to your filing this opinion as an exhibit to the Registration
Statement and the reference to our firm under the headings "The Mergers--
Material Federal Income Tax Consequences of the Mergers" and "Legal Matters."
 
                                          Very truly yours,
 
                                          O'MELVENY & MYERS LLP