Exhibit 23.3
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We consent to the incorporation by reference in this Amendment No. 1 to Registration Statement No. 333-162077 of our report dated April 2, 2007, relating to the consolidated financial statements of US LEC Corp. and subsidiaries (the “Company”) (which report expresses an unqualified opinion and includes an explanatory paragraph referring to the completion of the merger between the Company and PAETEC Corp. on February 28, 2007, pursuant to the Merger Agreement dated August 11, 2006, as amended), appearing in the Registration Statement on Form S-3 of PAETEC Holding Corp. (File No. 333-159344).
We also consent to the reference to us under the heading “Experts” in the Prospectus which is part of this Registration Statement.
| /s/ DELOITTE & TOUCHE LLP |
| Charlotte, North Carolina |
| September 30, 2009 |
