August 20, 2019

Aoife Brennan
Chief Executive Officer
Synlogic, Inc.
301 Binney St., Suite 402
Cambridge, MA 02142

       Re: Synlogic, Inc.
           Registration Statement on Form S-3
           Filed August 8, 2019
           File No. 333-233139

Dear Dr. Brennan:

       We have limited our review of your registration statement to those
issues we have
addressed in our 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 amending your registration statement
and providing the
requested information. 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 any amendment to your registration statement and the
information you
provide in response to these comments, we may have additional comments.

Registration Statement on Form S-3

General

1.     We note that your forum selection provision identifies the Court of
Chancery of the
       State of Delaware as the exclusive forum for certain litigation,
including any
       "derivative action." Please describe this provision and disclose whether
this provision
       applies to actions arising under the Securities Act or Exchange Act. In
that regard, we
       note that Section 27 of the Exchange Act creates exclusive federal
jurisdiction over all
       suits brought to enforce any duty or liability created by the Exchange
Act or the rules and
       regulations thereunder, and Section 22 of the Securities Act creates
concurrent jurisdiction
       for federal and state courts over all suits brought to enforce any duty
or liability created by
       the Securities Act or the rules and regulations thereunder. If the
provision applies to
       Securities Act claims, please also revise your prospectus to state that
there is uncertainty
 Aoife Brennan
Synlogic, Inc.
August 20, 2019
Page 2
      as to whether a court would enforce such provision and that investors
cannot waive
      compliance with the federal securities laws and the rules and regulations
thereunder. If
      this provision does not apply to actions arising under the Securities Act
or Exchange Act,
      please also tell us how you will inform investors in future filings that
the provision does
      not apply to any actions arising under the Securities Act or Exchange
Act.
        We remind you that the company and its management are responsible for
the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action
or absence of
action by the staff.

       Refer to Rules 460 and 461 regarding requests for acceleration. Please
allow adequate
time for us to review any amendment prior to the requested effective date of
the registration
statement.

        Please contact Tonya K. Aldave at (202) 551-3601 or Justin Dobbie,
Legal Branch Chief,
at (202) 551-3469 with any questions.



                                                            Sincerely,
FirstName LastNameAoife Brennan
                                                            Division of
Corporation Finance
Comapany NameSynlogic, Inc.
                                                            Office of
Healthcare & Insurance
August 20, 2019 Page 2
cc:       Daniel Bagliebter, Esq.
FirstName LastName