Mail Stop 6010	January 18, 2006

Mr. Stanley C. Erck
Chief Executive Officer
Iomai Corporation
20 Firstfield Road, Suite 250
Gaithersburg, Maryland 20878

Re:	Iomai Corporation
      Amendment No. 4 to Registration Statement on Form S-1
Filed January 9, 2006
File No. 333-128765

Dear Mr. Erck:

      We have reviewed your filing and have the following
comments.
Where indicated, we think you should revise your document in
response
to these comments.  If you disagree, we will consider your
explanation as to why our comment is inapplicable or a revision is
unnecessary.  Please be as detailed as necessary in your
explanation.
In some of our comments, we may ask you to provide us with
supplemental information so we may better understand your
disclosure.
After reviewing this information, we may or may not raise
additional
comments.

      Please understand that the purpose of our review process is
to
assist you in your compliance with the applicable disclosure
requirements and to enhance the overall disclosure in your filing.
We look forward to working with you in these respects.  We welcome
any questions you may have about our comments or on any other
aspect
of our review.  Feel free to call us at the telephone numbers
listed
at the end of this letter.

General

1. We note the reference to a phase 1/2 clinical trial for your
needle-free flu vaccine patch.  In order to use the term 1/2, we
require that the study meet the requirements of both phase 1 and
phase 2.  Please confirm that the phase 1/2 clinical trial is
expected to meet the requirements of both phase 1 and phase 2.
Otherwise, revise to eliminate the reference to phase 1/2.  If you
retain the reference to phase 1/2, please disclose if you expect
to
conduct a phase 2 trial after the phase 1/2 trial or proceed
directly
to a phase 3 trial.


Risk Factors

"Our directors and management will exercise significant control .
.. .
.." Page 23

2. Please revise your disclosure to also state the percentage of
your
outstanding common stock that your directors and executive
officers
and their affiliates will collectively control after the offering,
assuming the 958,333 shares are purchased in the offering by your
existing investors or their affiliates.

Certain relationships and related party transactions, page 82

3. Please revise your disclosure regarding the preferred stock
sale
by Elan to disclose the sale price of the Series B preferred
stock.


*	*	*	*	*


      As appropriate, please amend your filing in response to
these
comments.  You may wish to provide us with marked copies of the
amendment to expedite our review.  Please furnish a cover letter
with
your amendment that keys your responses to our comments and
provides
any requested supplemental information.  Detailed cover letters
greatly facilitate our review.  Please file your cover letter on
EDGAR under the form type label CORRESP. Please understand that we
may have additional comments after reviewing your amendment and
responses to our comments.

      We direct your attention to Rules 460 and 461 regarding
requesting acceleration of a registration statement.  Please allow
adequate time after the filing of any amendment for further review
before submitting a request for acceleration.  Please provide this
request at least two business days in advance of the requested
effective date.


You may contact Tabatha Akins at (202) 551-3658 or Oscar Young at
(202) 551-3622 if you have questions regarding comments on the
financial statements and related matters.  Please contact Sonia
Barros at (202) 551-3655 or Suzanne Hayes at (202) 551-3675 with
any
other questions.


								Sincerely,



								Jeffrey P. Riedler
								Assistant Director

cc:	Paul M. Kinsella, Esq.
Ropes & Gray LLP
One International Place
Boston, MA 02110-2624

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Mr. Stanley C. Erck
January 18, 2006
Page 1