Exhibit 21 DIRECT AND INDIRECT OPERATING SUBSIDIARIES OF FIRSTMERIT CORPORATION* Citizens Investment Corporation Citizens Savings Corporation of Stark County FirstMerit Bank, National Association - Abell & Associates, Inc. - Alpha Equipment Group, Inc. - FirstMerit Commercial Insurance Agency, Inc. - FirstMerit Insurance Agency, Inc. - FirstMerit Leasing Company - FirstMerit Mortgage Corporation - FirstMerit Mortgage Reinsurance Company, Inc. (Hawaii) - FirstMerit Securities, Inc. - FirstMerit Title Agency, Ltd. - FMTP, LLC (Delaware) - Home Financial Services Corp. - Mobile Consultants, Inc. - Signal Finance Company - FMRC, Inc. (Delaware) - FMS, Inc. (Delaware) FirstMerit Capital Trust I (Delaware) FirstMerit Community Development Corporation FirstMerit Credit Life Insurance Company (Arizona) FMT, Inc. (Delaware) SF Development Corp. * Unless otherwise indicated, state of formation is Ohio.