Exhibit 31.2

CERTIFICATIONS

I, David I. Matson, certify that:

     1.   I have  reviewed  this  quarterly  report on Form 10-Q of  UnionBanCal
          Corporation (the "Registrant");

     2.   Based on my  knowledge,  this  quarterly  report  does not contain any
          untrue  statement of a material  fact or omit to state a material fact
          necessary to make the statements  made, in light of the  circumstances
          under which such  statements were made, not misleading with respect to
          the period covered by this quarterly report;

     3.   Based on my knowledge,  the financial statements,  and other financial
          information  included in this quarterly report,  fairly present in all
          material respects the financial  condition,  results of operations and
          cash flows of the Registrant as of, and for, the periods  presented in
          this quarterly report;

     4.   The Registrant's  other  certifying  officer and I are responsible for
          establishing  and maintaining  disclosure  controls and procedures (as
          defined  in  Exchange  Act  Rules  13a-15(e)  and  15d-15(e)  for  the
          Registrant and we have:

          a)   designed such disclosure controls and procedures,  or caused such
               disclosure  controls  and  procedures  to be  designed  under our
               supervision,  to ensure that material information relating to the
               Registrant,  including  its  consolidated  subsidiaries,  is made
               known to us by others within those entities,  particularly during
               the period in which this quarterly report is being prepared;

          b)   evaluated  the  effectiveness  of  the  Registrant's   disclosure
               controls  and   procedures  and  presented  in  this  report  our
               conclusions  about the  effectiveness of the disclosure  controls
               and  procedures,  as of the  end of the  period  covered  by this
               report based on such evaluation;

          c)   disclosed in this quarterly report any change in the Registrant's
               internal  control over financial  reporting that occurred  during
               the  Registrant's  most recent fiscal  quarter (the  Registrant's
               fourth fiscal  quarter in the case of an annual  report) that has
               materially  affected,  or  is  reasonably  likely  to  materially
               affect,   the   Registrant's   internal  control  over  financial
               reporting; and


<PAGE>



     5.   The Registrant's other certifying officer and I have disclosed,  based
          on our most recent  evaluation,  to the Registrant's  auditors and the
          audit  committee  of  Registrant's  board  of  directors  (or  persons
          performing the equivalent function):

          a)   all  significant  deficiencies  and  material  weaknesses  in the
               design or operation of internal control over financial  reporting
               which are reasonably  likely to adversely affect the Registrant's
               ability  to  record,  process,  summarize  and  report  financial
               information; and

          b)   any fraud,  whether or not material,  that involves management or
               other employees who have a significant  role in the  Registrant's
               internal control over financial reporting.


Date:  August 14 , 2003


                            By:             /s/  DAVID I. MATSON
                                   --------------------------------------
                                                 David I. Matson
                                            EXECUTIVE VICE PRESIDENT
                                            CHIEF FINANCIAL OFFICER
                                         (Principal Financial Officer)






















                                       2