Exhibit 5.1
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                          GOODWIN, PROCTER & HOAR LLP
                               COUNSELORS AT LAW
                                 EXCHANGE PLACE
                        BOSTON, MASSACHUSETTS 02109-2881



                                January 19, 1999



Boston Properties, Inc.
8 Arlington Street
Boston, MA 02116

Ladies and Gentlemen:

     This opinion is furnished in connection with the registration on Form S-3
(the "Registration Statement") pursuant to the Securities Act of 1933, as
amended (the "Securities Act"), of the issuance of up to 1,471,456 shares (the
"Redemption Shares") of common stock, par value $.01 per share ("Common Stock"),
of Boston Properties Inc. (the "Company").  The Redemption Shares may be issued
by the Company if and to the extent that common units of limited partnership
interest ("Redemption Units") in Boston Properties Limited Partnership, a
Delaware limited partnership (the "Operating Partnership"), that were originally
issued to John F. Griffin, George G. Mulligan, Barbara Huppe, Barry M.
Fitzpatrick, David E. Schutt, Charles A. Salcetti, Nancy M. Griffin, Caroline A.
Griffith, David M. Whitmer, George H. Beuchert, III, Cynthia A. Benedetti, The
Donald  N. Coupard Revocable Trust, The Patricia E. Coupard Revocable Trust,
Tech Park 270 Phase III Limited Partnership, Tech Park 270 Limited Partnership,
Decoverly Two Limited Partnership, Reston Town Center Office Park Phase One
Limited Partnership, MGA Virginia 85-1 Limited Partnership, MGA Virginia 86-2
Limited Partnership, Decoverly Four Limited Partnership, Decoverly Five Limited
Partnership, Decoverly Six Limited Partnership, Decoverly Seven Limited
Partnership, Reston Corporate Center Limited Partnership, and MGA Virginia 96-1
Limited Partnership, in connection with the acquisition of properties in
Maryland and Virginia on February 1, 1998, are presented to the Operating
Partnership for redemption (which may occur at any time on or after February 11,
1999) and the Company exercises its right under the partnership agreement of the
Operating Partnership to acquire such Redemption Units in exchange for shares of
Common Stock.

     In connection with rendering this opinion, we have examined the Amended and
Restated Certificate of Incorporation and Amended and Restated Bylaws of the
Company, each as amended to date; such records of the corporate proceedings of
the Company as we deemed material; and such other certificates, receipts,
records and documents as we considered necessary for the purposes of this
opinion.  In our examination, we have assumed the 

 
Boston Properties, Inc.
January 19, 1999
Page 2

genuineness of all signatures, the legal capacity of natural persons, the
authenticity of all documents submitted to us as certified, photostatic or
facsimile copies, the authenticity of the originals of such copies and the
authenticity of telephonic confirmations of public officials and others. As to
facts material to our opinion, we have relied upon certificates or telephonic
confirmations of public officials and certificates, documents, statements and
other information of the Company or representatives or officers thereof.

     We are attorneys admitted to practice in The Commonwealth of Massachusetts.
We express no opinion concerning the laws of any jurisdictions other than the
laws of the United States of America, the laws of The Commonwealth of
Massachusetts, and the Delaware General Corporation Law.

     Based upon the foregoing, we are of the opinion that, when the Redemption
Shares have been issued in exchange for Redemption Units tendered to the
Operating Partnership for redemption as contemplated by the limited partnership
agreement of the Operating Partnership, such Redemption Shares will be validly
issued, fully paid and nonassessable.

     The foregoing assumes that all requisite steps were taken to comply with
the requirements of the Securities Act and applicable requirements of state laws
regulating the offer and sale of securities.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to us with respect to this opinion
under the heading "Legal Matters" in the Prospectus which is a part of such
Registration Statement.  In giving such consent, we do not thereby admit that we
are in the category of persons whose consent is required under Section 7 of the
Act.

                                    Very truly yours,

                                    /s/ GOODWIN, PROCTER & HOAR LLP

                                    GOODWIN, PROCTER & HOAR LLP