United States securities and exchange commission logo June 10, 2021 Timothy C. Dec Chief Financial Officer OPGEN INC 9717 Key West Avenue, Suite 100 Rockville, MD 20850 Re: OPGEN INC Registration Statement on Form S-3 Filed June 4, 2021 File No. 333-256820 Dear Mr. Dec: 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 or Fredrick Philantrope at 202-551- 6875 with any questions. Sincerely, Division of Corporation Finance Office of Life Sciences cc: Peter Jaslow, Esq.