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/ MASAAKI TANAKA
                                                ______________
                                                Masaaki Tanaka


                                            Date:    3/26/07