EXHIBIT 32(a)

Certification Pursuant to Section 1350 of Chapter 63

of Title 18 of the United States Code

I, William D. Perez, the Chief Executive Officer of Wm. Wrigley Jr. Company (the “Company”), certify that to the best of my knowledge:

(i) the Annual Report of the Company on the Form 10-K dated February 11, 2008 for the fiscal year ended December 31, 2007, fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(ii) the information contained in the said Form 10-K fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ WILLIAM D. PEREZ

William D. Perez

President and Chief Executive Officer

Date: February 11, 2008