Exhibit 24

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Richard A. Abdoo                                   

Richard A. Abdoo

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ David L. Andreas                              

David L. Andreas

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Andrew N. Baur                                 

Andrew N. Baur

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Jon F. Chait                                           

Jon F. Chait

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Bruce E. Jacobs                                    

Bruce E. Jacobs

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Ted D. Kellner                               

Ted D. Kellner

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Dennis J. Kuester                               

Dennis J. Kuester

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as her true and lawful attorney-in-fact for the purpose of:  (i) executing in her name and on her behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in her name and on her behalf in her capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming her signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Katharine C. Lyall                              

Katharine C. Lyall

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ John A. Mellowes                          

John A. Mellowes

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Edward L. Meyer, Jr.                     

Edward L. Meyer, Jr.

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ San W. Orr, Jr.                                   

San W. Orr, Jr.

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Robert J. O’Toole                                  

Robert J. O’Toole

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Peter M. Platten, III                          

Peter M. Platten, III

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ Robert A. Schaefer                          

Robert A. Schaefer

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ John S. Shiely                                   

John S. Shiely

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ James A. Urdan                                 

James A. Urdan

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as her true and lawful attorney-in-fact for the purpose of:  (i) executing in her name and on her behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in her name and on her behalf in her capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming her signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s Debra S. Waller                                         

Debra S. Waller

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ George E. Wardeberg                           

George E. Wardeberg

DIRECTOR’S POWER OF ATTORNEY

The undersigned director of Marshall & Ilsley Corporation designates each of Dennis J. Kuester, John M. Presley and Randall J. Erickson, with the power of substitution, as his true and lawful attorney-in-fact for the purpose of:  (i) executing in his name and on his behalf Marshall & Ilsley Corporation’s Registration Statement on Form S-4, to which this power of attorney is filed as an exhibit, and any related amendments (including post-effective amendments) and/or supplements to said Form S-4 (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended); (ii) generally doing all things in his name and on his behalf in his capacity as a director to enable Marshall & Ilsley Corporation to comply with the provisions of the Securities Exchange Act of 1934, as amended, the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission; and (iii) ratifying and confirming his signature as it may be signed by the attorney-in-fact to the Form S-4 and any related amendments (including post-effective amendments) and/or supplements thereto (or any other registration statement for the same offering that is to be effective upon filing pursuant to Rule 462(b) under the Securities Act of 1933, as amended).

Dated this 21st day of October, 2004.

/s/ James B. Wigdale                            

James B. Wigdale