Exhibit 5.0  Opinion of Muldoon, Murphy & Faucette LLP
                     re: Legality 
     

               {LETTERHEAD OF MULDOON, MURPHY AND FAUCETTE LLP]
 
                               February 2, 1999



Board of Directors
PFSB Bancorp, Inc.
123 West Lafayette Street
Palmyra, Missouri 63461

          Re:  The offering of up to 859,625 shares of
               PFSB Bancorp, Inc. Common Stock
               -------------------------------

Ladies and Gentlemen:

     You have requested our opinion concerning certain matters of Missouri law
in connection with the conversion of Palmyra Saving and Building Association,
F.A. (the "Bank"), a federally-chartered savings association, from the mutual
form of ownership to a federally-chartered capital stock savings bank to be
named Palmyra Savings (the "Conversion"), and the related subscription offering,
community offering and syndicated community offering (the "Offerings") by PFSB
Bancorp, Inc., a Missouri corporation (the "Company"), of up to 747,500 shares
of its common stock, par value $.01 per share ("Common Stock") (859,625 shares
if the Estimated Valuation Range is increased up to 15% to reflect changes in
market and financial conditions following commencement of the Offerings).

     In connection with your request for our opinion, you have provided to us
and we have reviewed the Company's articles of incorporation filed with the
Secretary of State, Corporate Division of Missouri on November 25, 1998 (the
"Articles of Incorporation"); the Company's Bylaws; the Company's Registration
Statement on Form SB-2, as filed with the Securities and Exchange Commission
initially on December 18, 1998, and as amended (the "Registration Statement");
the ESOP trust agreement and the ESOP loan agreement; resolutions of the Board
of Directors of the Company (the "Board") concerning the organization of the
Company, the Offerings and designation of a Pricing Committee of the Board, and
the form of stock certificate approved by the Board to represent shares of
Common Stock. We have also been furnished a certificate of the Secretary of
State, Corporation Division of Missouri, certifying the Company's good standing
as a Missouri corporation. Capitalized terms used but not defined herein shall
have the meaning given them in the Articles of Incorporation.


 
Board of Directors
PFSB Bancorp, Inc.
February 2, 1999
Page 2

     We understand that the Company will loan to the trust for the Bank's
Employee Stock Ownership Plan (the "ESOP") the funds the ESOP Trust will use to
purchase shares of Common Stock for which the ESOP Trust subscribes pursuant to
the Offerings and for purposes of rendering the opinion set forth below, we
assume that: (a) the Board of Directors of the Company has duly authorized the
loan to the ESOP Trust (the "Loan"); (b) the ESOP serves a valid corporate
purpose for the Company; (c) the Loan will be made at an interest rate and on
other terms that are fair to the Company; (d) the terms of the Loan will be set
forth in customary and appropriate documents including, without limitation, a
promissory note representing the indebtedness of the ESOP Trust to the Company
as a result of the Loan; and (e) the closing for the Loan and for the sale of
Common Stock to the ESOP Trust will be held after the closing for the sale of
the other shares of Common Stock sold in the Offerings and the receipt by the
Company of the proceeds thereof.

     Based upon and subject to the foregoing, and limited in all respects to
matters of Missouri law, it is our opinion that:

     Upon the due adoption by the Pricing Committee of a resolution fixing the
number of shares of Common Stock to be sold in the Offerings, the Common Stock
to be issued in the Offerings (including the shares to be issued to the ESOP
Trust) will be duly authorized and, when such shares are sold and paid for in
accordance with the terms set forth in the Prospectus and such resolution of the
Pricing Committee and certificates representing such shares substantially in the
form provided to us and included in Exhibit 4.0 to the Registration Statement
are duly and properly issued, will be validly issued, fully paid and
nonassessable.

     The following provisions of the Articles of Incorporation may not be given
effect by a court applying Missouri law, but in our opinion the failure to give
effect to such provisions will not affect the duly authorized, validly issued,
fully paid and nonassessable status of the Common Stock:

          Subsections 3.2(c) and (f) of ARTICLE III and Section 10.5 of Article
          X, which grant the Board the authority to construe and apply the
          provisions of those Articles, subsection 3.2(d) of Article III, to the
          extent that subsection obligates any person to provide to the Board
          the information such subsection authorizes the Board to demand,
          subsection 3.2(a) of Article III, to the extent that subsection limits
          the amount of shares of Common Stock a shareholder may vote, and
          Subsection 10.3(h) of Article X empowering the Board to determine the
          Fair Market Value of property offered or paid for the Company's stock
          by an Interested Shareholder, in each case to the extent, if any, that
          a court applying Missouri law were to impose equitable limitations
          upon such authority.


 
Board of Directors
PFSB Bancorp, Inc.
February 2, 1999
Page 3

     We consent to the filing of this opinion as an exhibit to the Registration
Statement on Form SB-2 and the Form AC and to the use of the name of our firm
where it appears in the Registration Statement, Form AC and Prospectus.

                                    Very truly yours,


                                    /s/ Muldoon, Murphy & Faucette LLP
 
                                    MULDOON, MURPHY & FAUCETTE LLP