Exhibit 5

                              April 12, 2000


Hologic, Inc.
35 Crosby Drive
Bedford, MA 01730-1401

RE:  Registration Statement on Form S-8

Ladies and Gentlemen:

     We are general counsel to Hologic, Inc., a Delaware
corporation (the "Company").  We have been asked to deliver this
opinion in connection with the preparation and filing with the
Securities and Exchange Commission under the Securities Act of
1933, as amended (the "Act"), of a Registration Statement on Form
S-8 (the "Registration Statement") relating to (i) 500,000 shares
of the Company's Common Stock, $.01 par value (the "Shares")
which may be issued pursuant to options granted under the
Company's 1997 Employee Equity Incentive Plan (the "1997 Plan");
and (ii) 500,000 Rights (as defined below) that may be issued in
connection with the issuance of the Shares pursuant to options
granted under the 1997 Plan.  The Rights are issuable pursuant to
that certain Rights Agreement, dated as of December 22, 1992, as
amended by Amendment No. 1, dated December 14, 1995, Amendment
No. 2, dated as of December 9, 1996, and Amendment No. 3, dated
as of April 25, 1999 (together, 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.

     In connection with this opinion, we have examined and are
familiar with originals or copies, certified or otherwise
identified to our satisfaction, of the following documents
(collectively, the "Documents"):

     1.   a copy of the Certificate of Incorporation of the Company as
          in effect on the date hereof;

     2.   a copy of the Bylaws of the Company as in effect on the date
          hereof;

     3.   the corporate records of the Company relating to the
          proceedings of stockholders and directors of the Company;

     4.   the 1997 Plan;

     5.   the Rights Agreement; and

     6.   the Registration Statement.

     In giving our opinion, we have relied as to matters of fact
upon certificates of officers of the Company.  For purposes of
this opinion we have assumed without any investigation (1) the
legal capacity of each natural person and (2) the genuineness of
each signature, the completeness of each document submitted to us
as an original and the conformity with the original of each
document submitted to us as a copy.

     Our opinion hereafter expressed is based solely upon (1) our
review of the Documents, (2) discussions with certain officers of
the Company with respect to the Documents, (3) discussions with
those of our attorneys who have devoted substantive attention to
the matters contained herein and (4) such review of published
sources of law as we have deemed necessary.

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

     (1) the  Shares  have  been duly  authorized  and,  when
         issued  in  accordance with the terms of  the  1997  Plan,
         will be validly issued, fully paid and nonassessable; and

     (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
         nonassessable.

     We hereby consent to the filing of this opinion as Exhibit 5
to the Registration Statement and to the reference to our firm
wherever it appears in the Registration Statement.

                              Very truly yours,

                              BROWN, RUDNICK, FREED & GESMER
                              By:  Brown, Rudnick, Freed &
                                   Gesmer, Ltd., a partner


                              By: /s/ Jayne M. Donegan
                                   -----------------------
                                    Jayne M. Donegan, a Member
                                    hereunto duly authorized