United States securities and exchange commission logo

                          November 28, 2022

       Dr. Andrew Allen
       Chief Executive Officer and Director
       Gritstone bio, Inc.
       5959 Horton Street, Suite 300
       Emeryville, California 94608

                                                        Re: Gritstone bio, Inc.
Statement on Form S-3
                                                            Filed November 22,
                                                            File No. 333-268524

       Dear Dr. Andrew Allen:

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

               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 Cindy
Polynice at 202-551-8707 with any questions.


                          Division of Corporation Finance

                          Office of Life Sciences
       cc:                                              Brian Cuneo