EXHIBIT 23 CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS We consent to the incorporation by reference in Registration Statement No. 333-75521 on Form S-8 of Mercantile Bank Corporation and Mercantile Bank of West Michigan 401(k) Plan of our report dated April 17, 2003 appearing in this Annual Report on Form 11-K of Mercantile Bank of West Michigan 401(k) Plan for the year ended December 31, 2002. Crowe Chizek and Company LLC Grand Rapids, Michigan June 25, 2003