
                                                EXHIBIT 5.01

                              August 9, 1999

Hologic, Inc.
35 Crosby Drive
Bedford, MA 01730

Attn:     S. David Ellenbogen, Chief Executive Officer

     RE:  Registration Statement on Form S-3 filed on August 5, 1999
     ---------------------------------------------------------------
Ladies and Gentlemen:

     We  have  acted as counsel to Hologic, Inc., a Delaware
corporation   (the  "Company"),  in  connection   with   the
preparation  and  filing  with the Securities  and  Exchange
Commission  of  a Registration Statement on  Form  S-3  (the
"Registration Statement") pursuant to which the  Company  is
registering  under the Securities Act of  1933,  as  amended
(the  "Act"),  a total of 1,857,142 shares of common  stock,
$.01  par  value  (the  "Shares") and 1,857,142  Rights,  as
defined  below.   The Rights are issuable pursuant  to  that
certain  Rights Agreement, dated as of April 22,  1992  (the
"Rights  Agreement"), providing, in effect, for the delivery
of  a  right  (a "Right"), along with each share  of  Common
Stock issued by the Company.  This opinion is being rendered
in connection with the filing of the Registration Statement.

     In  connection with this opinion, we have examined  the
following documents (collectively, the "Documents"):

     (i)   the  Certificate of Incorporation of the  Company
           incorporated by reference as Exhibit  3.01  to  the
           Registration Statement;
     (ii)  the By-laws of the Company incorporated by reference as
           Exhibit 3.02 to the Registration Statement;
     (iii) the corporate minute books and other records of
           the Company;
     (iv)  the Securities Purchase Agreement dated April 28, 1999,
           as amended on June 3, 1999 by and among the Company,
           Sterling Diagnostic Imaging, Inc. and SDI Investments,
           L.L.C.;
     (v)   the Contract of Sale dated April 28, 1999, as amended
           on June 3, 1999 by and among the Company and Glasgow Land
           Company, L.L.C.;
     (vi)  the Rights Agreement;
     (vii) a letter dated August 4, 1999 from American Stock
           Transfer & Trust Company, the Company's transfer agent, as
           to the number of issued and outstanding shares of the
           Company as of a recent date; and
    (viii) the Registration Statement.

      We  have,  without independent investigation,  relied
upon  the  representations and warranties  of  the  various
parties  as to matters of objective fact contained  in  the
Documents.

       We   have   not  made  any  independent  review   or
investigation   of  orders,  judgments,  rules   or   other
regulations or decrees by which the Company or any  of  its
property  may  be  bound, nor have we made any  independent
investigation  as  to  the  existence  of  actions,  suits,
investigations   or  proceedings,  if   any,   pending   or
threatened against the Company.

      The  opinions expressed herein are based solely  upon
(i)  our review of the Documents, (ii) discussions with  S.
David  Ellenbogen,  the Chairman of  the  Board  and  Chief
Executive  Officer of the Company and Glenn  P.  Muir,  the
Company's  Vice  President of Finance and Treasurer,  (iii)
discussions  with those of our attorneys who  have  devoted
substantive attention to the matters contained herein,  and
(iv)  such  review of published sources of law as  we  have
deemed necessary.

     This  firm,  in  rendering legal opinions,  customarily
makes certain assumptions which are described in Schedule  A
hereto.   In the course of our representation of the Company
in   connection   with  preparation  of   the   Registration
Statement, nothing has come to our attention which causes us
to  believe  reliance  upon  any  of  those  assumptions  is
inappropriate,  and,  with  your concurrence,  the  opinions
hereafter expressed are based upon those assumptions.

     We  express no legal opinion upon any matter other than
those  explicitly addressed in numbered paragraphs 1  and  2
below, and our express opinions therein contained shall  not
be  interpreted  to  be an implied opinion  upon  any  other
matter.

     Our  opinions  contained  herein  are  limited  to  the
Delaware General Corporation Law and the Federal law of  the
United States of America.

     Based upon and subject to the foregoing, we are of  the
opinion that:

     1.    The  Shares have been duly authorized and validly
issued, and are fully paid and non-assessable.

     2.    The  Rights have been duly authorized  and,  when
issued in accordance with the terms of the Rights Agreement,
will be validly issued, fully paid and non-assessable.

     We  understand  that this opinion  is  to  be  used  in
connection  with the Registration Statement.  We consent  to
the   filing  of  this  opinion  as  an  Exhibit   to   said
Registration  Statement and to the  reference  to  our  firm
wherever it appears in the Registration Statement, including
the   prospectus  constituting  a  part  thereof   and   any
amendments  thereto.  This opinion may be used in connection
with  the offering of the Shares only while the Registration
Statement,  as it may be amended from time to time,  remains
effective under the Act.

                         Very truly yours,

                         BROWN, RUDNICK, FREED & GESMER

                         By: BROWN, RUDNICK, FREED & GESMER, P.C., a Partner

                         By: /s/   Philip  J.   Flink
                             --------------------------
                             Philip J. Flink, A Member
                              Duly Authorized



                         SCHEDULE A

               BROWN, RUDNICK, FREED & GESMER
                    STANDARD ASSUMPTIONS


       In   rendering   legal  opinions   in   third   party
transactions,  Brown, Rudnick, Freed & Gesmer makes  certain
customary assumptions described below:

           1.                      Each   natural   person
           executing  any  of the Documents  has  sufficient
           legal  capacity to enter into such Documents  and
           perform the transactions contemplated thereby.

           2.                        The    Company    holds
           requisite  title  and  rights  to  any   property
           involved  in  the transactions described  in  the
           Documents and purported to be owned by it.

           3.                     Each person other than the
           Company has all requisite power and authority and
           has taken all necessary corporate or other action
           to  enter into those Documents to which it  is  a
           party  or  by  which it is bound, to  the  extent
           necessary   to  make  the  Documents  enforceable
           against it.

           4.                     Each person other than the
           Company  has complied with all legal requirements
           pertaining  to its status as such status  relates
           to  its  rights to enforce the Documents  against
           the Company.

           5.                     Each Document is accurate,
           complete   and   authentic,  each   original   is
           authentic,  each  copy conforms to  an  authentic
           original and all signatures are genuine.

           6.                        All   official   public
           records   are  accurate,  complete  and  properly
           indexed and filed.

           7.                      There  has not  been  any
           mutual   mistake  of  fact  or  misunderstanding,
           fraud, duress, or undue influence by or among any
           of the parties to the Documents.

           8.                     The conduct of the parties
           to  the  transactions described in the  Documents
           has  complied in the past and will comply in  the
           future  with any requirement of good faith,  fair
           dealing and conscionability.

           9.                     Each person other than the
           Company  has  acted  in good  faith  and  without
           notice of any defense against the enforcement  of
           any  rights created by, or adverse claim  to  any
           property  or  security  interest  transferred  or
           created as part of, the transactions described in
           the Documents.

           10.                    There are no agreements or
           understandings among the parties to or  bound  by
           the Documents, and there is no usage of trade  or
           course of prior dealing among such parties,  that
           would define, modify, waive, or qualify the terms
           of any of the Documents.

           11.                     The Company will  not  in
           the   future   take   any  discretionary   action
           (including a decision not to act) permitted under
           any Document that would result in a violation  of
           law  or constitute a breach or default under that
           or  any other Document or court or administrative
           orders,  writs, judgments and decrees  that  name
           the  Company and are specifically directed to  it
           or its property.

           12.                     The  Company will  obtain
           all   permits  and  governmental  approvals   not
           required  at  the  time of  the  closing  of  the
           transactions  contemplated by the  Documents  but
           which  are  subsequently required, and will  take
           all  actions  similarly  required,  relevant   to
           subsequent   consummation  of  the   transactions
           contemplated  by the Documents or performance  of
           the Documents.

             13.  All  parties to or bound by the  Documents
           will  act  in  accordance with, and will  refrain
           from taking any action that is forbidden by,  the
           terms and conditions of the Documents.




