EXHIBIT 23.1

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption “Experts” and to the use of our reports dated November 15, 2005, in the Registration Statement (Form S-1 No. 333-    ) and related Prospectus of Eagle Test Systems, Inc. dated December 20, 2005.

/s/ Ernst & Young LLP  

Chicago, Illinois
December 19, 2005