EXHIBIT 5/EXHIBIT 23.1
                                                          ----------------------


                     Opinion of Thacher Proffitt & Wood LLP



                   [LETTERHEAD OF THACHER PROFFITT & WOOD LLP]






May 21, 2004


Board of Directors
Westbank Corporation
225 Park Avenue
West Springfield, MA 01089


                  Re: Registration Statement on Form S-8
                      ----------------------------------

Members of the Board:

         We have acted as counsel for Westbank Corporation, a Massachusetts
corporation (the "Company"), in connection with the filing of a registration
statement on Form S-8 under the Securities Act of 1933, as amended
("Registration Statement") with respect to 92,505 shares of the Company's common
stock, par value $2.00 per share (the "Common Stock"), to be offered pursuant to
the Westbank Corporation 2004 Recognition and Retention Plan (the "Plan").

         In rendering the opinion set forth below, we do not express any opinion
concerning law other than the laws of the Commonwealth of Massachusetts and the
federal securities laws of the United States.

         We have examined originals or copies, certified or otherwise
identified, of such documents, corporate records and other instruments as we
have deemed necessary or advisable for purposes of this opinion. As to matters
of fact, we have examined and relied upon the Plan described above and, where we
have deemed appropriate, representations or certificates of officers of the
Company or public officials. We have assumed the authenticity of all documents
submitted to us as originals, the genuineness of all signatures, the legal
capacity of natural persons and the conformity to the originals of all documents
submitted to us as copies.



Board of Directors
Westbank Corporation
May 21, 2004                                                              Page 2


         Based on the foregoing, we are of the opinion that the shares of Common
Stock that are being registered pursuant to the Registration Statement have been
duly authorized and, when issued and paid for in accordance with the terms of
the Plan, such shares will be validly issued, fully paid and non-assessable.

         This opinion is given solely for the benefit of the Company and
purchasers of shares under the Plan, and may not be relied upon by any person or
entity, nor quoted in whole or in part, or otherwise referred to in any document
without our express written consent.

         We consent to the filing of this opinion as an exhibit to the
Registration Statement and to the references to our firm's name therein.


                                            Very truly yours,


                                            THACHER PROFFITT & WOOD LLP



                                            By: /s/ Richard A. Schaberg
                                                --------------------------------
                                                Richard A. Schaberg, Esq.