Exhibit 15.1

Board of Directors and Stockholders
Arthur J. Gallagher & Co.


We are aware of the incorporation by reference in the Registration Statements
(Form S-8, No. 33-604 and Form S-8, No. 33-14625) pertaining to the Arthur J.
Gallagher & Co. Incentive and United Kingdom Incentive Plans, in the
Registration Statements (Form S-8, No. 33-24251, Form S-8, No. 33-38031 and Form
S-8, No. 333-57155) pertaining to the Arthur J. Gallagher & Co. 1988 Incentive
and 1988 Nonqualified Stock Option Plans, in the Registration Statement (Form
S-8, No. 33-30816) pertaining to the Arthur J. Gallagher & Co. Non-Employee
Directors' Stock Option Plan, in the Registration Statements (Form S-8, No.
33-64614 and Form S-8, No. 33-80648) pertaining to the Arthur J. Gallagher & Co.
1988 Incentive, 1988 Nonqualified, and Non-Employee Directors' Stock Option
Plans, in the Registration Statements (Form S-8, No. 333-06359, Form S-8, No.
333-40000 and Form S-8, No. 333-87320) pertaining to the Arthur J. Gallagher &
Co. 1988 Nonqualified and Non-Employee Directors' Stock Option Plans, in the
Registration Statement (Form S-8, No. 333-62930) pertaining to the Arthur J.
Gallagher & Co. 1988 Nonqualified and Non-Employee Directors' Stock Option Plans
and the Gallagher Healthcare Insurance Services, Inc. 2001 Nonqualified Stock
Option Plan, in the Registration Statements (Form S-4, No. 333-75197, Form S-3,
No. 333-84139 and Form S-4, No. 333-55254), and in the related Prospectuses, of
our review report dated May 15, 2003 relating to the unaudited consolidated
interim financial statements of Arthur J. Gallagher & Co. that are included in
its Quarterly Report on Form 10-Q for the quarter ended March 31, 2003.



                                  /s/ Ernst & Young LLP
                                 ---------------------------------------
                                            Ernst & Young LLP


Chicago, Illinois
May 15, 2003