EXHIBIT 5
                                                                ---------

                        OPINION OF STEWART S. HUDNUT

                    [ILLINOIS TOOL WORKS INC. LETTERHEAD]


   August 8, 2003

   Illinois Tool Works Inc.
   3600 West Lake Avenue
   Glenview, IL  60025

   Ladies and Gentlemen:

   I have acted as counsel for Illinois Tool Works Inc. (the
   "Registrant") in connection with the registration under the Securities
   Act of 1933, as amended, of 5,499,279 shares (the "Shares") of the
   Registrant's Common Stock, on a Registration Statement on Form S-8
   (the "Registration Statement") filed with the Securities and Exchange
   Commission.  The Shares are issuable in connection with the Illinois
   Tool Works Inc. 1996 Stock Incentive Plan (the "Plan").

   As General Counsel of the Registrant, I am familiar with the actions
   taken by the Registrant to authorize the registration of the Shares,
   including board approval on March 18, 2003 of the increase in the
   number of shares authorized for issuance under the Plan, stockholder
   approval on May 9, 2003 of such increase and the merger of the Premark
   International, Inc. 1994 Incentive Plan into the Plan, and board
   approval on August 8, 2003 of the filing of this Registration
   Statement with respect to the Shares.  I also participated in the
   preparation of the Registration Statement and have examined such other
   documents and legal authorities as I have deemed relevant for purposes
   of this opinion.

   Based upon the foregoing, I am of the opinion that the Shares, when
   issued in accordance with the terms of the Plan, will be duly
   authorized, validly issued and fully paid and nonassessable.

   I consent to the reference to me under item 5 in the Registration
   Statement and to the filing of this opinion as an exhibit to the
   Registration Statement.

   Very truly yours,

   /s/ Stewart S. Hudnut

   Stewart S. Hudnut