Mail Stop 6010


	October 10, 2006


Valentin P. Gapontsev, Ph.D.
Chief Executive Officer and Chairman of the Board
IPG Photonics Corporation
50 Old Webster Road
Oxford, Massachusetts  01540

      Re:	IPG Photonics Corporation
      Amendment No. 1 to Registration Statement on Form S-1
      Filed on September 27, 2006
		File No. 333-136521

Dear Dr. Gapontsev:

      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
information so we may better understand your disclosure.  After
reviewing this information, we may 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 any other aspect
of
our review.  Feel free to call us at the telephone numbers listed
at
the end of this letter.

We are subject to lawsuits, page 8

1. We note your response to prior comment 12; however, it remains
unclear whether the lawsuits affect:
* all of your products;
* products that contribute a substantial potion of your revenue;
* critical components of your product; or
* ancillary features of your products.
Therefore, we reissue the comment.

We rely on the significant experience, page 11

2. Please revise this risk factor to reflect the substance of the
first sentence of your response to prior comment 39.

We are subject to various environmental laws, page 16

3. Please clarify when you must be compliant with the RoHS
Directive.
Also clarify the status of the required redesign.

4. Please confirm our understanding that your statement in the
first
paragraph regarding compliance with current environmental laws and
regulations refers to the costs of compliance with the RoHS
directive.  If not, please clarify which laws and regulations will
require the additional costs and why you are not currently in
compliance.

We are subject to export control, page 17

5. We note your revisions in response to prior comment 18.  Please
clarify the duration and conditions of your licenses.  Must you
obtain a new license for each export?

Use of Proceeds, page 22

6. We note your response to prior comment 22; however, Regulation
S-K
Item 504 requires that you disclose the approximate amount for
each
purpose.  Therefore, we reissue the comment.

Competition, page 64

7. With a view toward disclosure, please tell us the competitive
effect of recently announced silicon lasers.

Certain Relationships and Related Party Transactions, page 82

8. Please expand your response to prior comment 44 to clarify
which
exhibits you have omitted because the agreements have been
terminated.  Also tell us the authority on which you rely for the
omission.

9. Please expand your response to prior comment 47 to tell us the
authority on which you rely to omit the disclosure.  Was the
former
officer a related party at the time of the transaction?

Transactions with IP Fibre Devices, page 82

10. We note your response to prior comment 49. With a view toward
clarified disclosure, please tell us the portion of IPFD`s assets
that are comprised of your securities.

11. Please clarify the nature of the August 2000 corporate
restructuring so that it is clear to investors why IPFD would
receive
securities in connection with your acquisition of IPG Lasers.

12. Please disclose the substance of the fourth and fifth
sentences
of your response to prior comment 50.

Transactions with NTO ITR-Polus, page 82

13. We note your reference to profit distributions from NTO IRE-
Polus
in your response to prior comment 66.  With a view toward
disclosure,
please tell us about how profits are distributed and the amount
distributed to your affiliates.

14. Please revise the second bullet point to explain the extent to
which you are not able to control the outcome of all corporate
action
due to the provisions requiring unanimous approval as mentioned in
your response to prior comment 66.

Series B Preferred Stockholders, page 84

15. Please disclose in this section the exercise price of the
warrants sold as part of the Series B transaction.

16. With a view toward clarified disclosure, please show us how
the
formula mentioned in the third paragraph generates the numbers in
the
table you provided in your response to prior comment 54.

Series D Preferred Stockholder, page 86

17. Please reconcile the number of shares underlying the preferred
stock as disclosed in this section with the disclosure in your
beneficial ownership table.

18. With a view toward clarified disclosure, please tell us:
* the nature of the contract dispute with JDS Uniphase;
* the nature of the components it supplied to you under the
disputed
contract, including the materiality of the components to your
products;
* the extent to which the products you sell to JDS Uniphase under
the
settlement permit JDS Uniphase to compete with you;
* the nature of the products you purchase from JDS Uniphase under
the
settlement; and
* the amount of product you purchased from JDS Uniphase under the
settlement.

Financial Statements, page F-1

Note 7 - Convertible Redeemable Preferred Stock, Preferred Stock
and
Warrants, page F-17

19. Please refer to prior comments 63 and 65.  Please respond to
the
following:
* We note from your response to prior comment 63 that "The Company
has concluded that the holders` option to convert the series B
preferred stock to equity at any time does not qualify the equity
conversion option as a derivative..." We further note from your
response to prior comment 65 that "...the Company has concluded
that
there are two embedded derivatives..." in their series B preferred
stock, one of which was an equity conversion option.  Please
clarify
for us how you concluded that the same host instrument both does
and
does not include embedded derivatives as a result of its equity
conversion option and further clarify why your accounting for the
conversion options is appropriate.
* Additionally we note that you concluded that the equity
conversion
option qualified for equity classification as it satisfied all of
the
requirements specified in paragraphs 12-32 of EITF 00-19.  Please
provide us with details of your analysis of these paragraphs in
EITF
00-19 for the series B preferred stock.
* Additionally we note that if your qualified public offering is
between $25.00 and $62.50 per share, the conversion value becomes
fixed at $237,500,000.  Please tell us and revise the filing to
disclose what this number represents and how it was calculated.
* Finally, please revise your disclosures to clearly describe how
you
are accounting for and valuing the conversion options and any
embedded derivatives.

Recent Sales of Unregistered Securities, page II-3

20. We reissue prior comment 67 which sought disclosure of the
facts
relied on to make the cited exemption available, rather than just
disclosure of the exemption.

21. We note the increase in the number of outstanding securities
disclosed on page 88; however, the disclosure in this section has
not
changed.  Please advise.

Exhibits

22. Please file complete exhibits with all attachments.  For
example,
we note the missing exhibits mentioned in the agreement filed as
exhibit 10.32.

Exhibit 21

23. Please provide all information required by Regulation S-K Item
601(b)(21), including the jurisdiction of incorporation or
organization of each identified subsidiary.
*  *  *  *  *
      As appropriate, please amend your registration statement 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 information.  Detailed cover
letters greatly facilitate our review.  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 Eric Atallah at (202) 551-3663 or Jay Webb at
(202) 551-3603 if you have questions regarding comments on the
financial statements and related matters.  Please contact Tim
Buchmiller at (202) 551-3635 or me at (202) 551-3617 with any
other
questions.

      					Sincerely,



      					Russell Mancuso
      					Branch Chief

cc (via fax): 	Robert W. Ericson, Esq.
		David A. Sakowitz, Esq.
Valentin P. Gapontsev, Ph.D.
IPG Photonics Corporation
October 10, 2006
Page 6