EXHIBIT 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in Registration Statement No. 333-58295 on Form S-8 of the MainSource Financial Group, Inc. 401(k) and Employee Stock Ownership Plan of our report dated June 25, 2007, appearing in this Annual Report on Form 11-K of the MainSource Financial Group, Inc. 401(k) and Employee Stock Ownership Plan for the year ended December 31, 2006.

Crowe Chizek and Company LLC

South Bend, Indiana

June 27, 2007