As filed with the Securities and Exchange Commission on January 19, 2001
                                             Registration Statement No. 33-80773
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                             ----------------------

                        POST-EFFECTIVE AMENDMENT NO. 2 TO

                                    FORM S-3

             REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
                             ----------------------

                                  DIACRIN, INC.

             (Exact name of registrant as specified in its charter)
                             ----------------------


          DELAWARE                                           22-3016912
(State or other jurisdiction                              (I.R.S. Employer
of incorporation organization)                           Identification No.)


                              CHARLESTOWN NAVY YARD
                            BUILDING 96, 13TH STREET
                        CHARLESTOWN, MASSACHUSETTS 02129
                                 (617) 242-9100
                        (Address, including zip code, and
                     telephone number, including area code,
                            of registrant's principal
                               executive offices)

                             ----------------------

                                THOMAS H. FRASER
                      PRESIDENT AND CHIEF EXECUTIVE OFFICER
                                  DIACRIN, INC.
                              CHARLESTOWN NAVY YARD
                            BUILDING 96, 13TH STREET
                        CHARLESTOWN, MASSACHUSETTS 02129
                                 (617) 242-9100
                     (Name, address, including zip code, and
                     telephone number, including area code,
                              of agent for service)

                                    Copy to:

                             Steven D. Singer, Esq.
                                HALE AND DORR LLP
                                 60 State Street
                           Boston, Massachusetts 02109
                                 (617) 526-6000

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO PUBLIC:  NOT APPLICABLE.
If the only securities  being registered on this Form are being offered pursuant
to dividend or interest reinvestment plans, please check the following box. |__|





         If any of the  securities  being  registered  on  this  Form  are to be
offered  on a  delayed  or  continuous  basis  pursuant  to Rule 415  under  the
Securities Act of 1933,  other than  securities  offered only in connection with
dividend or interest reinvestment plans, check the following box. |__|

         If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the  Securities  Act  registrations  statement  number  of the  earlier
effective registration statement for the same offering. |__|

         If this  Form is a  post-effective  amendment  filed  pursuant  to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act  registration   statement  number  of  the  earlier  effective  registration
statement for the same offering. |__|

     If delivery of the  prospectus is expected to be made pursuant to Rule 434,
please check the following box. |__|

                                      -2-

================================================================================





                                Explanatory Note

                             ----------------------

         On December 22,  1995,  we filed a  registration  statement on Form S-2
(File No. 33-80773) registering, among other securities, 2,875,000 shares of our
common stock,  $.01 par value per share,  issuable upon the exercise of warrants
that we issued pursuant to a Unit and Warrant Agreement dated February 12, 1996,
by and between  Diacrin and  American  Stock  Transfer and Trust  Company.  This
registration statement was originally declared effective on February 12, 1996.

     On  June  24,  1996,  we  filed  post-effective  amendment  No.  1  to  the
registration statement on Form S-2 (File No. 33-80773) for the purpose of, among
other things, converting it into a registration statement on Form S-3.

     The warrants  expired in  accordance  with their terms on December 31, 2000
and are no longer exercisable.  Accordingly, this post-effective amendment No. 2
is being filed for the purpose of  deregistering  2,872,005 shares of our common
stock that had been reserved for issuance upon the exercise of the warrants, but
were not issued.



                                      -3-




                                   SIGNATURES

         Pursuant to Rule 478  promulgated  under the Securities Act of 1933, as
amended,  the registrant has duly caused this post-effective  amendment No. 2 to
be signed on its behalf by the undersigned,  thereunto duly  authorized,  in the
City of Boston, Commonwealth of Massachusetts on the 19th day of January, 2001.


                                             DIACRIN, INC.



                                             By:  /s/ Thomas H. Fraser
                                                -------------------------
                                                      Thomas H. Fraser
                                                      President and CEO



                                      -4-