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                          November 9, 2020

       Fred M. Schwarzer
       Chief Executive Officer and President
       IGM Biosciences, Inc.
       325 E. Middlefield Road
       Mountain View, California 94043

                                                        Re: IGM Biosciences,
Inc.
                                                            Registration
Statement on Form S-3
                                                            Filed November 5,
2020
                                                            File No. 333-249863

       Dear Mr. Schwarzer:

              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 Tim
Buchmiller at (202) 551-3635 with any questions.




                          Sincerely,


                          Division of Corporation Finance

                          Office of Life Sciences
       cc:                                              Tony Jeffries, Esq.