April 9, 2019

Charles Wilson
Chief Executive Officer
Unum Therapeutics Inc.
200 Cambridge Park Drive, Suite 3100
Cambridge, MA 02140

       Re: Unum Therapeutics Inc.
           Registration Statement on Form S-3
           Filed April 2, 2019
           File No. 333-230678

Dear Mr. Wilson:

       This is to advise you that we have not reviewed and will not review your
registration
statement.

        Please refer to Rules 460 and 461 regarding requests for acceleration.
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.

       Please contact Sonia Bednarowski at 202-551-3666 with any questions.



                                                            Sincerely,

                                                            Division of
Corporation Finance
                                                            Office of
Healthcare & Insurance