EXHIBIT 23.0 CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTANT We consent to the incorporation by reference in following documents of our report dated February 27, 2004, with respect to the 2003 consolidated financial statements of CFS Bancorp, Inc. incorporated by reference in this Annual Report (Form 10-K) for the year ended December 31, 2004: o Registration Statement (Form S-8 No. 333-62053) pertaining to the Citizens Financial Services, FSB Employees' Savings and Profit Sharing Plan and Trust. o Registration Statement (Form S-8 No. 333-62049) pertaining to the Stock Options Assumed in the Acquisition of SuburbFed Financial Corp. o Registration Statement (Form S-8 No. 333-84207) pertaining to the 1998 Stock Option Plan of CFS Bancorp, Inc. o Registration Statement (Form S-8 No. 333-105687) pertaining to the 2003 Stock Option Plan of CFS Bancorp, Inc. /s/ Ernst & Young LLP Chicago, Illinois March 14, 2005