EXHIBIT 5




                          Cadwalader, Wickersham & Taft
                                 100 Maiden Lane
                               New York, NY 10038
                                  (212)504-6000


                                December 14, 1999

OXiGENE, Inc.
110 East 59th Street
New York, NY 10022

            Re:   OXiGENE, Inc.
                  Registration of Stock Incentive Plan on Form S-8

Ladies and Gentlemen:

            We have acted as counsel for OXiGENE,  Inc., a Delaware  corporation
(the "Company"), in connection with the preparation and filing of a registration
statement on Form S-8 (the "S-8 Registration Statement"),  to which this opinion
is Exhibit 5, and pursuant to which the Company proposes to offer and sell up to
an aggregate of 1,260,419 shares ("Employee Option Shares") of its Common Stock,
par value $0.01 per share ("Common  Stock").  You have requested that we furnish
our opinion as to the matters hereinafter set forth.

            In rendering  the opinions  set forth  below,  we have  examined and
relied  upon  the  originals,  copies  or  specimens,   certified  or  otherwise
identified  to  our   satisfaction,   of:  (i)  the  Restated   Certificate   of
Incorporation  of the Company,  as  certified  by the  Secretary of State of the
State of Delaware on June 3, 1996;  (ii) the By-Laws of the Company,  as amended
on April 26,  1993;  (iii) the  resolutions  of the  Board of  Directors  of the
Company (the "Board"),  dated November 16, 1999 (the  "Resolutions"),  approving
the filing of the S-8  Registration  Statement and ratifying the  reservation of
the Employee  Option Shares;  (iv) the OXiGENE,  Inc. 1996 Stock  Incentive Plan
(the "Plan"), as amended; and (v) the S-8 Registration Statement.

            In  such   examination  we  have  assumed  the  genuineness  of  all
signatures,  the  authenticity  of all documents,  certificates  and instruments
submitted to us as originals, the conformity to original documents, certificates
and instruments of all documents,  certificates and instruments  submitted to us
as copies or specimens,  the  authenticity  of the originals of such  documents,
certificates  and  instruments  submitted to us as copies or specimens,  and the
accuracy of the matters set forth in the documents, certificates and instruments
we reviewed.  Except as expressly set forth herein,  we have not  undertaken any
independent investigation (including, without limitation, conducting any review,
search or  investigation  of any public files,  records or dockets) to determine
the existence or absence of the facts that are material to our opinions,  and no
inference  as to our  knowledge  concerning  such facts should be drawn from our
reliance  on  the   representations  of  the  Company  in  connection  with  the
preparation and delivery of this letter.

            We have relied upon the written representations of the Company as to
the accuracy and  completeness of (1) the By-Laws of the Company;  (2) the Plan;
(3) the S-8 Registration Statement; and (4) the Resolutions. We also have relied
upon the written





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OXiGENE, Inc.                                                December 14, 1999




representations  of the  Company  that the  Resolutions  and the  By-Laws of the
Company have not been amended or revoked.

            We have also assumed  (other than with respect to the Company)  that
all documents,  certificates and instruments have been duly authorized, executed
and  delivered by all parties  thereto,  that all such parties had the power and
legal  right to  execute  and  deliver  all  such  documents,  certificates  and
instruments,  and that such documents,  certificates  and instruments are valid,
binding and enforceable obligations of such parties.

            We express no opinion  concerning the laws of any jurisdiction other
than the laws of the State of New York and, to the extent expressly  referred to
in this opinion letter, the federal laws of the United States of America.  While
we are not licensed to practice law in the State of Delaware,  we have  reviewed
applicable  provisions of the Delaware General Corporation Law as we have deemed
appropriate  in  connection  with  the  opinions  expressed  herein.  Except  as
described,  we have neither  examined nor do we express any opinion with respect
to Delaware law.

            Based upon and subject to the foregoing,  we are of the opinion that
all of the Employee  Option  Shares have been duly  authorized  for issuance and
when (i) the S-8 Registration  Statement shall have become  effective,  (ii) the
Employee  Option Shares shall have been issued in the proposed  form,  and (iii)
the Employee Option Shares shall have been issued and delivered  against payment
therefor as contemplated  by the Plan,  will be validly  issued,  fully paid and
non-assessable.

            We hereby consent to the filing of this opinion as an exhibit to the
S-8 Registration Statement.

                                    Very truly yours,



                               /s/  Cadwalader, Wickersham & Taft