EXHIBIT 5.1
                            [TOMB & TOMB LETTERHEAD]




December 23, 2003


First Commonwealth Financial Corporation
Old Courthouse Square
22 North Sixth Street
Indiana, Pennsylvania 15701

RE:  First Commonwealth Financial Corporation Registration Statement on Form S-3

Ladies and Gentlemen:

         We have represented First Commonwealth Financial Corporation ("FCFC")
in connection with the preparation of a Registration Statement on Form S-3 (the
"Registration Statement") registering shares (the "Shares") of FCFC's common
stock, $1.00 par value, under the Securities Act of 1933, as amended (the
"Act"), to be issued in accordance with the Company's Dividend Reinvestment Plan
(the "Plan").

         In connection with this opinion, we have reviewed (a) the Registration
Statement, (b) the Plan and (c) such other documents as we have deemed necessary
to form the opinion expressed below. We have assumed the genuineness of all
signatures, the authenticity of all documents submitted to us, the conformity to
original documents of all documents submitted to us as copies and the
authenticity of the originals of such copies. As to various questions of fact
material to such opinion, we have relied upon statements of officers of FCFC.

         Based upon the foregoing, we are of the opinion that the Shares, when
issued pursuant to the Plan against payment therefor as provided in the Plan,
will be validly issued, fully paid and non-assessable.

         We consent to the filing of this opinion as an exhibit to the
Registration Statement and to the reference to this firm in the Registration
Statement under the caption "Legal Matters." In giving this consent, we do not
admit that we are experts within the meaning of the Act.

                                   Sincerely,

                                   /s/ David R. Tomb, Jr.