Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement Nos. 333-162996 on Form S-3, 333-139509 and 333-151571 each on Form S-8 of our reports dated March 15, 2010, relating to the consolidated financial statements of IPG Photonics Corporation and subsidiaries, and the effectiveness of IPG Photonics Corporation’s internal control over financial reporting, appearing in this Annual Report on Form 10-K of IPG Photonics Corporation for the year ended December 31, 2009.

/s/ Deloitte & Touche LLP

Boston, Massachusetts
March 15, 2010