April 24, 2020

Jeffrey Hatfield
Chief Executive Officer
Zafgen, Inc.
3 Center Plaza, Suite 610
Boston, MA 02108

       Re: Zafgen, Inc.
           Amendment 1 to Preliminary Proxy Statement on Schedule 14A
           Filed April 10, 2020
           File No. 001-36510

Dear Mr. Hatfield:

      We have reviewed your amended 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. Unless
we note
otherwise, our references to prior comments are to comments in our April 4,
2020 letter.

Amendment 1 to Schedule 14A filed April 10, 2020

Summary, page 1

1.     We note your response to our prior Comment 1. Please further revise your
disclosure to
       note that you are dependent on the intellectual property for the
development of certain of
       your early-stage product candidates and identify such early-stage
product candidates.
Chondrial's Business
Overview, page 159

2.     We note your response to our prior Comment 3. We also note that you
state that you do
       not believe that the referenced studies are material to Chondrial's
business. Please either
       (i) expand your disclosure to discuss the significance (or lack of
significance) to
 Jeffrey Hatfield
Zafgen, Inc.
April 24, 2020
Page 2
       Chondrial's business; or (ii) remove the disclosure.
Chondrial's Strategy, page 160

3.     We note your response to our prior Comment 4. We also note your revision
to your
       disclosure on page 159 and note no changes to page 160. We reissue our
prior Comment
       4. Please further revise your disclosure to remove any implication that
Chondrial will be
       successful in obtaining regulatory approval for CTI-1601 in an
accelerated manner.
        You may contact Michael Fay at (202) 551-3812 or Vanessa Robertson at
(202) 551-
3649 if you have questions regarding comments on the financial statements and
related
matters. Please contact Courtney Lindsay at (202) 551-7237 or Celeste Murphy at
(202) 551-
3257 with any other questions.



                                                              Sincerely,
FirstName LastNameJeffrey Hatfield
                                                              Division of
Corporation Finance
Comapany NameZafgen, Inc.
                                                              Office of Life
Sciences
April 24, 2020 Page 2
cc:       Andrew Goodman, Esq.
FirstName LastName