United States securities and exchange commission logo

                           May 19, 2021

       Gerrit Dispersyn, Dr. Med. Sc
       President and Chief Executive Officer
       Phio Pharmaceuticals Corp.
       257 Simarano Drive, Suite 101
       Marlborough, MA 01752

                                                        Re: Phio
Pharmaceuticals Corp.
Statement on Form S-3
                                                            Filed May 13, 2021
                                                            File No. 333-256100

       Dear Dr. Dispersyn:

              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 Jeffrey
Gabor at 202-551-2544 with any questions.


                           Division of Corporation Finance

                           Office of Life Sciences
       cc:                                              Ryan A. Murr, Esq.