December 12, 2019

Evan Jones
Chief Executive Officer
OpGen, Inc.
708 Quince Orchard Road, Suite 205
Gaithersburg, MD 20878

       Re: OpGen, Inc.
           Registration Statement on Form S-4
           Filed November 12, 2019
           File No. 333-234657

Dear Mr. Jones:

       We have reviewed your registration statement and have the following
comments. In
some of our comments, we may ask you to provide us with information so we may
better
understand your disclosure.

       Please respond to this letter by amending your registration statement
and providing the
requested information. If you do not believe our comments apply to your facts
and
circumstances or do not believe an amendment is appropriate, please tell us why
in your
response.

       After reviewing any amendment to your registration statement and the
information you
provide in response to these comments, we may have additional comments.

Registration Statement on Form S-4 filed November 12, 2019

Cover Page

1.     Please disclose the expected ownership percentages of Curetis N.V. and
OpGen
       shareholders.
2.     We note that you will be issuing 2,662,564 shares of Common Stock as the
sole
       consideration pursuant to the Implementation Agreement. Please revise
the cover page to
       provide the approximate value of the merger consideration. Please also
disclose that the
       market value of the shares to be issued could vary significantly from
the market value as
       of the date of the proxy statement/prospectus.
 Evan Jones
FirstName LastNameEvan Jones
OpGen, Inc.
Comapany12, 2019
December NameOpGen, Inc.
Page 2
December 12, 2019 Page 2
FirstName LastName
Proxy Statement/Prosepctus Summary
OpGen, page 1

3.       We note that in July 2019, you received an Additional Information
Request from the FDA
         detailing a number of questions relating to your 510(k) application
for your Acuitas AMR
         Gene Panel (Isolates) diagnostic test. Please expand your disclosure
here, and in the risk
         factor on page 13, to describe the additional information requested.
What is required to consummate the Transaction?, page 42

4.       Please revise to identify the conditions that the parties may waive.
Background of the Transaction, page 49

5.       Please revise your disclosure throughout this section to provide
greater detail as to the
         background of the transaction, including the material issues discussed
and key negotiated
         terms. The disclosure should provide shareholders with an
understanding of how, when,
         and why the material terms of your proposed transaction evolved and
why this transaction
         is being recommended as opposed to any alternatives. In your revised
disclosure, please
         ensure that you address the following:
           the material terms for any proposals and subsequent proposals and
counter offers;
           valuations;
           negotiation of the transaction documents and the parties involved;
and
           at what point other strategic alternatives were eliminated from
consideration.
6.       With reference to the disclosure on page 52 regarding the 19 companies
that executed
         non-disclosure agreements and received the CIM, as well as the
conversations and
         evaluation of potential transactions with the entities described in
this paragraph, please
         revise to clarify whether any proposals were received. If proposals
were received, please
         revise to disclose the material terms.
7.       We note the disclosure on page 3 that the number of shares
representing the Consideration
         would equal 32.3% of the outstanding shares of OpGen common stock.
Please revise the
         disclosure on page 55 to explain how the equity allocation of 72.5%
contained in the
         principal term sheet evolved into 32.3%.
8.       Please supplementally provide us with copies of all materials prepared
by Crosstree and
         shared with your board of directors and their representatives,
including copies of all board
         books and all transcripts and summaries, that were material to the
board's decision to
         approve the Implementation Agreement.
Opinion of OpGen's Financial Advisor, page 57

9.       In the analyses where Crosstree examined selected companies or
transactions for the
         purposes of comparison, please disclose whether any companies or
transactions that met
         the selection criteria were excluded from the analysis and why.
 Evan Jones
FirstName LastNameEvan Jones
OpGen, Inc.
Comapany12, 2019
December NameOpGen, Inc.
Page 3
December 12, 2019 Page 3
FirstName LastName
Public Trading Multiples Analysis, page 59

10.      We note your disclosure that some of the companies used in the Public
Trading Multiples
         Analysis may have financial and operating characteristics that are
materially different
         from those of OpGen. For each of the companies used by Crosstree for
their analysis,
         please disclose the underlying data for the companies such as the
number of products or
         services and whether such products and services have received
marketing clearance in the
         United States.
Discounted Cash Flow Analysis, page 61

11.      We note the description of the discounted cash flow analysis prepared
by Crosstree. We
         further note that Crosstree relied on projections prepared by OpGen's
management when
         preparing the discounted cash flow analysis. Please revise your
description of this
         analysis to disclose the projections used.
Unaudtied Pro Forma Condensed Combined Financial Information, page 81

12.      Please provide an analysis that describes how you considered and that
clearly explains
         how you weighted each of the following factors in concluding that
OpGen was the
         accounting acquirer in the planned Transaction, giving particular
detail on
         possible reduction in the 67.7% ownership interest deemed to be held
by OpGen
         shareholders:

              the number of shares to be issued to Curetis N.V. under the
Implementation
              Agreement;
              the number of units and pre-funded units sold in the October 2019
Offering;
              the disclosure that the percentage of voting rights held by
OpGen's stockholders will
              continue to constitute a majority of the voting rights of the
combined company after
              the October 2019 Offering and after closing under the
Implementation Agreement,
              currently estimated at 67.7%;
              the contractual right held by Curetis N.V. to designate a
majority of the members of
              the initial board of directors of OpGen after the closing;
              the change in the chief executive officer of OpGen after the
closing to be the chief
              executive officer of Curetis N.V;
              the retention of the chief financial officer of OpGen as the
chief financial officer of
              Newco; and
              the agreement between OpGen and Curetis N.V. to add a seventh
director to the
              OpGen Board of Directors following the closing of the
Transaction, with such person
              recommended by OpGen.

         As part of your response, describe the background behind each of the
following
         disclosures and describe how these concerns may impact your accounting
treatment as of
         the date of the execution of the Implementation Agreement.
 Evan Jones
OpGen, Inc.
December 12, 2019
Page 4
              "The consummation of the October 2019 Offering had a substantial
impact on the
              final determination as to the accounting treatment of the
business combination."
              (page 81)
              "The pro forma adjustments are preliminary, subject to further
revision as additional
              information becomes available and additional analyses are
performed including but
              not limited to final assessment of the accounting acquirer...and
could have a material
              impact on the accompanying unaudited pro forma condensed combined
financial
              information and the combined company's future results of
operations and financial
              position." (page 82)
              "This anticipated accounting treatment differs from the
anticipated accounting
              treatment as of the date of the execution of the Implementation
Agreement, primarily
              as a result of the dilution caused by the October 2019 Offering."
(page 62)
Curetis' Business
Curetis' Partnering and Collaboration Agreements, page 140

13.      For each agreement discussed in this section, please expand your
disclosure to include the
         material terms including financial terms, duration of the agreements
and royalty terms,
         and termination provisions. Please also file these agreements as
exhibits or tell us why
         you are not required to do so. See Item 601(b)(10) of Regulation S-K.
Acquisition Agreements, page 143

14.      For your GEAR asset acquisition, please expand your disclosure to
include the material
         terms including financial terms (including the aggregate milestone
payments and royalty
         rate or range not to exceed ten percent) and the duration of the
royalty term. Please also
         file the GEAR and Gyronimo acquisition agreements as exhibits or tell
us why you are not
         required to do so. See Item 601(b)(10) of Regulation S-K.
Patents, page 160

15.      We note that you have 148 issued patents and patent applications in
various jurisdictions.
         Please revise to disclose for each material patent and patent
application the specific
         product(s) to which such patents or patent applications relate, the
type of patent
         protection, and applicable jurisdictions.
Material U.S. Federal Income Tax Consequences, page 184

16.    We note your disclosure that if the parties' tax treatment of the
Transaction is respected,
       the Transaction will not give rise to the recognition of gain or losses
to you or your
       stockholders for U.S. federal income tax purposes. Please file a tax
opinion as an exhibit
FirstName LastNameEvan Jones
       to the filing or provide us your analysis why the tax consequences are
not material to an
Comapany NameOpGen, Inc.no tax opinion is required to be filed. Refer to Item
601(b)(8) of
       investor and therefore
December 12, 2019 Page 4 Section III.A.2 of Staff Legal Bulletin 19.
       Regulation S-K and
FirstName LastName
 Evan Jones
FirstName LastNameEvan Jones
OpGen, Inc.
Comapany12, 2019
December NameOpGen, Inc.
December 12, 2019 Page 5
Page 5
FirstName LastName
Anti-Takeover Effects of Our Certificate of Incorporation, Bylaws and Delaware
Law
Exclusive Jurisdiction for Certain Actions, page 191

17.      We note that your forum selection provision identifies the Court of
Chancery of the State
         of Delaware as the sole and exclusive forum for certain litigation,
including any
         "derivative action." Please disclose whether this provision applies to
actions arising under
         the Securities Act or Exchange Act. In that regard, we note that
Section 27 of the
         Exchange Act creates exclusive federal jurisdiction over all suits
brought to enforce any
         duty or liability created by the Exchange Act or the rules and
regulations thereunder, and
         Section 22 of the Securities Act creates concurrent jurisdiction for
federal and state courts
         over all suits brought to enforce any duty or liability created by the
Securities Act or the
         rules and regulations thereunder. If the provision applies to
Securities Act claims, please
         also revise your prospectus to state that there is uncertainty as to
whether a court would
         enforce such provision and that investors cannot waive compliance with
the federal
         securities laws and the rules and regulations thereunder. If this
provision does not apply
         to actions arising under the Securities Act or Exchange Act, please
also ensure that the
         exclusive forum provision in the governing documents states this
clearly, or tell us how
         you will inform investors in future filings that the provision does
not apply to any actions
         arising under the Securities Act or Exchange Act.
Exhibits

18.      Please file the EIB Finance Contract as an exhibit, or tell us why you
do not believe it is
         required to be filed. Refer to Item 601(b)(10) of Regulation S-K.
General

19.      We note your statement under "References to Additional Information"
following the
         Cover Page, that you state that you "do not make any representation as
to the accuracy of
         the information" in the industry publications and research, surveys
and studies conducted
         by third parties. This statement appears to disclaim the issuer's
responsibility for
         information in the registration statement. Please revise.
        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.

       Refer to Rules 460 and 461 regarding requests for acceleration. Please
allow adequate
time for us to review any amendment prior to the requested effective date of
the registration
statement.
 Evan Jones
OpGen, Inc.
December 12, 2019
Page 6

       You may contact Franklin Wyman at 202-551-3660 or Kevin Vaughn at
202-551-3494 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Jeffrey Gabor at 202-551-2544 or Mary Beth Breslin at 202-551-3625 with
any other
questions.



                                                         Sincerely,
FirstName LastNameEvan Jones
                                                         Division of
Corporation Finance
Comapany NameOpGen, Inc.
                                                         Office of Life
Sciences
December 12, 2019 Page 6
cc:       Mary J. Mullany, Esq.
FirstName LastName