EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement on Form S-8, pertaining to the Hologic, Inc. Second Amended and Restated 1999 Equity Incentive Plan, of our reports dated December 11, 2006 with respect to the consolidated financial statements of Hologic, Inc. included in its Annual Report (Form 10-K) for the year ended September 30, 2006, Hologic Inc.’s management’s assessment of the effectiveness of internal control over financial reporting, and the effectiveness of internal control over financial reporting of Hologic Inc. filed with the Securities and Exchange Commission.

/s/ ERNST & YOUNG LLP

Boston, Massachusetts

December 11, 2006