United States securities and exchange commission logo February 2, 2021 Gerrit Dispersyn, Dr. Med. Sc. Chief Executive Officer Phio Pharmaceuticals Corp. 257 Simarano Drive, Suite 101 Marlborough, MA 01752 Re: Phio Pharmaceuticals Corp. Registration Statement on Form S-3 Filed January 29, 2021 File No. 333-252588 Dear Dr. Dispersyn: 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 Ada D. Sarmento at 202-551-3798 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Ryan A. Murr, Esq.