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                          April 4, 2022

       David Kirn, M.D.
       Chief Executive Officer
       4D Molecular Therapeutics, Inc.
       5858 Horton Street #455
       Emeryville, California 94608

                                                        Re: 4D Molecular
Therapeutics, Inc.
                                                            Registration
Statement on Form S-3
                                                            Filed March 29,
2022
                                                            File No. 333-263925

       Dear Dr. Kirn:

              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 Alan
Campbell at 202-551-4224 with any questions.




                          Sincerely,


                          Division of Corporation Finance

                          Office of Life Sciences
       cc:                                              Mark V. Roeder, Esq.