Exhibit 23.1

Consent of Independent Certified Public Accountants

We have issued our report dated May 19, 2006, accompanying the financial statements of The Unitil Corporation Tax Deferred Savings and Investment Plan contained in the information required by Form 11-K for the year ended December 31, 2005. We consent to the incorporation by reference of said report in the Registration Statement of the Unitil Corporation Tax Deferred Savings and Investment Plan on Form S-8 (File No. 333-42266, effective July 26, 2000).

/s/ Vitale, Caturano & Co.

Boston Massachusetts

June 26, 2006