<PAGE>
Exhibit 24
POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints James Dimon, Verne G. Istock, William P.
Boardman, Robert A. Rosholt, James L. Foorman, M. Eileen Kennedy and Laurence
Goldman, jointly and severally, his attorney-in-fact, each with power of
substitution, for him in any and all capacities to sign one or more Registration
Statements on Form S-3 relating to debt obligations of, warrants, options,
rights, preferred stock and common stock (the "Securities") of BANK ONE
CORPORATION (the "Corporation") and any amendments thereto (including any post-
effective amendments) and any subsequent registration statement filed by the
Corporation pursuant to Rule 462(b) of the Securities Act of 1933 with respect
to such Securities, in either case pursuant to resolutions adopted by the Board
of Directors of the Corporation on September 21, 1999, and to file the same,
with exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange Commission hereby ratifying and confirming all that each
of said attorneys-in-fact, or his substitute or substitutes, may do or cause to
be done by virtue hereof.
Signature Title
--------- -----
/s/ William P. Boardman Director
--------------------------------
William P. Boardman
/s/ John H. Bryan Director
--------------------------------
John H. Bryan
/s/ Siegfried Buschmann Director
--------------------------------
Siegfried Buschmann
/s/ James S.Crown Director
--------------------------------
James S. Crown
/s/ James Dimon Principal Executive Officer and Director
--------------------------------
James Dimon
/s/ Bennett Dorrance Director
--------------------------------
Bennett Dorrance
/s/ Dr. Maureen A. Fay, O.P. Director
--------------------------------
Dr. Maureen A. Fay, O.P.
/s/ John R. Hall Director
--------------------------------
John R. Hall
<PAGE>
/s/ Verne G. Istock Director
--------------------------------
Verne G. Istock
/s/ Laban P. Jackson, Jr. Director
--------------------------------
Laban P. Jackson, Jr.
/s/ John W. Kessler Director
--------------------------------
John W. Kessler
/s/ Richard A. Manoogian Director
--------------------------------
Richard A. Manoogian
/s/ William T.McCormick Director
--------------------------------
William T. McCormick
/s/ Thomas E. Reilly, Jr. Director
--------------------------------
Thomas E. Reilly, Jr.
/s/ John W. Rogers, Jr. Director
--------------------------------
John W. Rogers, Jr.
/s/ Thekla R. Shackelford Director
--------------------------------
Thekla R. Shackelford
/s/ Alex Shumate Director
--------------------------------
Alex Shumate
/s/ Frederick P. Stratton, Jr. Director
--------------------------------
Frederick P. Stratton, Jr.
________________________________ Director
Robert D. Walter
April 18, 2000
<PAGE>
/s/ James A. Peers Principal Accounting Officer
--------------------------------
James A. Peers
/s/ William J. Roberts Principal Financial Officer
--------------------------------
William J. Roberts
Dated: May 1, 2000
