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                           May 18, 2020

       Lloyd M. Segal
       Chief Executive Officer
       Repare Therapeutics Inc.
       7210 Frederick-Banting, Suite 100
       St-Laurent, Qu bec, Canada H4S 2A1

                                                        Re: Repare Therapeutics
Inc.
                                                            Amendment No. 1 to
Draft Registration Statement on Form S-1
                                                            Submitted May 12,
2020
                                                            CIK No. 0001808158

       Dear Mr. Segal:

             We have reviewed your amended draft registration statement and
have the following
       comments. In some of our comments, we may ask you to provide us with
information so we
       may better understand your disclosure.

              Please respond to this letter by providing the requested
information and either submitting
       an amended draft registration statement or publicly filing your
registration statement on
       EDGAR. If you do not believe our comments apply to your facts and
circumstances or do not
       believe an amendment is appropriate, please tell us why in your
response.

             After reviewing the information you provide in response to these
comments and your
       amended draft registration statement or filed registration statement, we
may have additional
       comments.

       Amendment No. 1 to Draft Registration Statement on Form S-1

       Intellectual Property, page 127

   1.                                                   We note your response
to prior comment 11. As indicated in your response, please revise
                                                        your disclosure to
clarify that the SL pairs that you may identify would not be patent-
                                                        eligible.
       Principal Shareholders, page 172

   2.                                                   We note your disclosure
in footnote 2 that Todd Foley may, collectively with the other
                                                        members of such
entities, be deemed to share voting and investment power with respect to
                                                        the shares held by each
of the MPM Entities. Please ensure that you have identified all
                                                        natural persons who
have or share beneficial ownership of the securities held by each of
 Lloyd M. Segal
Repare Therapeutics Inc.
May 18, 2020
Page 2
      the MPM Entities. Please also expand your disclosure in footnotes 4 and 5
to provide the
      disclosure requested by prior comment 15.
       You may contact Tracey McKoy at (202) 551-3772 or Kate Tillan at (202)
551-3604 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Tim Buchmiller at (202) 551-3635 or Celeste Murphy at (202) 551-3257
with any other
questions.



                                                          Sincerely,
FirstName LastNameLloyd M. Segal
                                                          Division of
Corporation Finance
Comapany NameRepare Therapeutics Inc.
                                                          Office of Life
Sciences
May 18, 2020 Page 2
cc:       Divakar Gupta, Esq
FirstName LastName