EXHIBIT 24



                                POWER OF ATTORNEY

     I do hereby constitute and appoint John H. McGuckin, Jr., Morris W. Hirsch,
and Vicki Wilderman, each individually,  with full power of substitution,  as my
true and lawful attorney-in-fact to:

     (1) sign and file on my behalf any and all Forms 3, 4 and 5 (including  any
amendments) as may be required to be filed with the U.S. Securities and Exchange
Commission  under  Section  16 of the  Securities  Exchange  Act and  any  stock
exchange or similar  authority as a result of my ownership of or transactions in
securities of UnionBanCal Corporation (the "Company"); and

     (2) take any other action of any type  whatsoever  which, in the opinion of
such attorney-in-fact,  may be necessary or desirable to complete,  sign or file
with the relevant  authorities  any such Form 3, 4 or 5, or any  amendments,  or
otherwise  of  benefit  to me  or in my  best  interest,  or  legally  required,
including filing the Form ID, in connection with the foregoing.

This Power of  Attorney  shall  remain in full  force and  effect  until I am no
longer  required  to file  Forms 3, 4 and 5 with  regard to my  ownership  of or
transactions  in  securities  of the  Company,  unless I  earlier  revoke  it in
writing.

I hereby ratify, approve and confirm all that any such attorney-in-fact,  or any
substitute,  may  lawfully  do and cause to be done by  virtue of this  Power of
Attorney.

I hereby  acknowledge  that John H. McGuckin,  Jr., Morris W. Hirsch,  and Vicki
Wilderman  are  not  assuming,   nor  is  the  Company   assuming,   any  of  my
responsibilities to comply with Section 16 of the Securities Exchange Act.


                                            /s/ MOHAN GYANI


                                            Date:    7/14/06