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                                                                      Exhibit 5

                               PALMER & DODGE LLP
                 One Beacon Street Boston, Massachusetts 01208

TELEPHONE:  (617) 573-0100                            FACSIMILE:  (617) 227-4420


                                 June 11, 1996


Genzyme Transgenics Corporation
Five Mountain Road
Framingham, Massachusetts 01701


     We are rendering this opinion in connection with the Registration
Statement on Form S-1 (the "Registration Statement") filed by Genzyme
Transgenics 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 up to 3,450,000 shares of the
Company's Common Stock, $0.01 par value (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. We are familiar with the proceedings of the Board of
Directors in connection with the authorization, issuance and sale of the Shares
(the "Resolutions"). We have examined such other 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, when issued and delivered by the Company against payment
therefor at the price to be determined pursuant to the Resolutions, will be
validly issued, fully paid and non-assessable.

     We hereby consent to the filing of this opinion as a part of the
Registration Statement and to the reference to our firm under the caption
"Legal Matters" in the Prospectus filed as part thereof.


                                  Very truly yours,


                                  /s/ Palmer & Dodge LLP