EXHIBIT 5.1

                          PILLSBURY MADISON & SUTRO LLP
                              235 Montgomery Street
                             San Francisco, CA 94104
                               Tel: (415) 983-1000


July 1, 1998




SJNB Financial Corp.
One North Market Street
San Jose, CA  95113


Re:      Registration Statement on Form S-8


Gentlemen:

With  reference  to the  Registration  Statement on Form S-8 to be filed by SJNB
Financial Corp., a California  corporation (the "Company"),  with the Securities
and Exchange  Commission  under the Securities Act of 1933,  relating to 150,000
shares of the Company's  Common Stock  issuable  pursuant to the Company's  1996
Stock Option Plan (the "Stock Plan"),  it is our opinion that such shares of the
Common Stock of the Company,  when issued and sold in accordance  with the Stock
Plan, will be legally issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion with the Securities and Exchange
Commission as Exhibit 5.1 to the Registration Statement.

Very truly yours,



S/PILLSBURY MADISON & SUTRO, LLP