EXHIBIT 21 SUBSIDIARIES OF THE COMPANY Central Co-operative Bank 100% owned by the Company, incorporated under the laws of the Commonwealth of Massachusetts. Central Securities Corporation 100% owned by the Bank, incorporated under the laws of the Commonwealth of Massachusetts. Central Securities Corporation II 100% owned by the Bank, incorporated under the laws of the Commonwealth of Massachusetts. Central Bancorp Capital Trust I 100% owned by the Company, incorporated under the laws of the State of Delaware