PERINI CORPORATION THIRD AMENDMENT

Exhibit 10.20

PERINI CORPORATION

THIRD AMENDMENT

THIS THIRD AMENDMENT (this “Amendment”) is entered into as of January 31, 2004 by and among PERINI CORPORATION, a Massachusetts corporation (the “Borrower”), with its chief executive office at 73 Mt. Wayte Avenue, Framingham, Massachusetts 01701, FLEET NATIONAL BANK, as Administrative Agent (the “Administrative Agent”), and the Lenders under the Credit Agreement, as defined below. Capitalized terms not otherwise defined herein shall have the meanings ascribed to them in the Credit Agreement, as defined below.

R E C I T A L S

WHEREAS, the Borrower, the Administrative Agent and the Lenders have previously entered into a Credit Agreement dated as of January 23, 2002, as amended by a First Amendment and Waiver dated as of February 14, 2003, and by a Second Amendment dated as of November 5, 2003 (the “Credit Agreement”);

WHEREAS, the Borrower has requested, and the Lenders have agreed, to make certain modifications to the Credit Agreement on the terms and conditions set forth herein;

NOW THEREFORE, in consideration of the foregoing premises and the mutual benefits to be derived by the Borrower, the Administrative Agent and the Lenders from a continuing relationship under the Credit Agreement and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereto agree as follows:

A.    Amendment to Credit Agreement. The defined term “Reduction Date” found in Section 1.01 of the Credit Agreement is hereby amended in its entirety to read as follows:

“Reduction Date” means April 30, 2004.

B.    Representations and Warranties. The Borrower represents and warrants to the Administrative Agent and the Lenders that: (a) the Borrower has the full power and authority to execute, deliver and perform its respective obligations under, the Credit Agreement, as amended by this Amendment, (b) the execution and delivery of this Amendment has been duly authorized by all necessary action of the Board of Directors of the Borrower; (c) the representations and warranties contained or referred to in Article IV of the Credit Agreement are true and accurate in all material respects as of the date of this Amendment; and (d) no Event of Default has occurred and is continuing or will result after giving effect to this Amendment and the transactions contemplated by this Amendment and the Credit Agreement.

C.    Other.

2.    This Amendment is executed as an instrument under seal and shall be governed by and construed in accordance with the laws of The Commonwealth of Massachusetts without regard to its conflicts of law rules. All parts of the Credit Agreement, the Financing Documents and the Fee Letter not affected by this Amendment are hereby ratified and affirmed in all respects, provided that if any provision of the Credit Agreement shall conflict or be inconsistent with this Amendment, the terms of this Amendment shall supersede and prevail. Upon the execution of this Amendment, all references to the Credit Agreement in that document, or in any related document, shall mean the Credit Agreement as amended by this Amendment. Except as expressly provided in this Amendment, the execution and delivery of this Amendment does not and will not amend, modify or supplement any provision of, or constitute a consent to or a waiver of any noncompliance with the provisions of the Credit Agreement, and, except as specifically provided in this Amendment, the Credit Agreement shall remain in full force and effect. This Amendment may be executed in one or more counterparts with the same effect as if the signatures hereto and thereto were upon the same instrument.

[SIGNATURE PAGE FOLLOWS]

IN WITNESS WHEREOF, each of the Borrower, the Administrative Agent and the Lenders in accordance with Section 9.05 of the Credit Agreement, has caused this Amendment to be executed and delivered by their respective duly authorized officers as of the date set forth in the preamble on page one of this Amendment.