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                                                                     Exhibit 5.1

                               PALMER & DODGE LLP
                                ONE BEACON STREET
                           BOSTON, MASSACHUSETTS 02108

Telephone: (617) 573-0100                             Facsimile: (617) 227-4420

                                        November 5, 1996

Genzyme Corporation
One Kendall Square
Cambridge, Massachusetts 02139

     We are rendering this opinion in connection with the Registration Statement
on Form S-3 (the "Registration Statement") filed by Genzyme Corporation (the
"Company") with the Securities and Exchange Commission under the Securities Act
of 1933, as amended, on or about the date hereof. The Registration Statement
relates to the registration of 4,830,000 shares of the Company's General        
Division Common Stock, $0.01 par value, and 326,025 shares of the Company's
Tissue Repair Division Common Stock, $0.01 par value (collectively, the
"Shares"). We understand that the Shares are to be offered and sold in the
manner described in the Registration Statement.

     We have acted as your counsel in connection with the preparation of the
Registration Statement and are familiar with the proceedings taken by the
Company in connection with the authorization and issuance of the Shares. We have
examined such documents as we consider necessary to render this opinion.

     Based upon the foregoing, we are of the opinion that the Shares have been
duly authorized, and upon issuance and delivery against payment therefor, will
be validly issued, fully paid and nonassessable.

     We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.

                                        Very truly yours,

                                        /s/ Palmer & Dodge LLP