Exhibit 5.1

                            CHOATE, HALL & STEWART
              A PARTNERSHIP INCLUDING PROFESSIONAL CORPORATIONS

                                EXCHANGE PLACE
                                53 STATE STREET
                       BOSTON, MASSACHUSETTS 02109-2891
                           TELEPHONE (617) 248-5000
                           FACSIMILE (617) 248-4000
                                 TELEX 49615860



                                                           May 14, 1997

Stratus Computer, Inc.
55 Fairbanks Boulevard
Marlborough, Massachusetts 01752

Ladies and Gentlemen:

         This opinion is delivered to you in  connection  with the  Registration
Statement on Form S-8 (the "Registration  Statement") to be filed  on  or  about
May 14, 1997 by Stratus  Computer, Inc. (the "Company") under the Securities Act
of  1933, as  amended, for  registration under  said Act  of 5,500,000 shares of
common stock, $.01 par value (the "Common Stock"), of the Company.

         We are  familiar  with  the  Company's  Articles  of  Organization,  as
amended, its By-Laws, as amended, and the records of its corporate  proceedings.
We have also examined such other  documents,  records and  certificates and made
such further  investigation as we have deemed necessary for the purposes of this
opinion.

         Based upon and subject to the foregoing, we are of the opinion that the
shares of Common  Stock to be sold by the  Company  under its Stock  Option Plan
(January,  1983), its Non-Qualified Common Stock Option Plan, its Employee Stock
Purchase Plan, and its 1997 Non-Qualified Common Stock Option Plan, as in effect
on the date hereof,  when issued  against  receipt of the agreed  purchase price
therefor, will be legally issued, fully paid and nonassessable.

         We understand  that this opinion is to be used in  connection  with the
Registration  Statement  and consent to the filing of this opinion as an exhibit
to the Registration  Statement. We further consent to the reference to this firm
under the heading  "Interests  of Named  Experts and  Counsel" in Part II of the
Registration Statement.

                                                    Very truly yours,

                                                    CHOATE, HALL & STEWART