EXHIBIT 21 SUBSIDIARIES OF THE REGISTRANT The following is a list of all subsidiaries of Premier Financial Bancorp, Inc. and their state of incorporation. Subsidiary State of Incorporation Citizens Deposit Bank and Trust Company Kentucky County Finance (a direct subsidiary of Citizens Deposit Bank and Trust Company) Kentucky Bank of Germantown Kentucky Georgetown Bancorp, Inc. Kentucky Georgetown Bank and Trust Company (a direct subsidiary of Georgetown Bancorp, Inc.) Kentucky Citizens Bank Kentucky Premier Data Services, Inc. Kentucky Farmers Deposit Bancorp, Inc. Kentucky Farmers Deposit Bank (a direct subsidiary of Farmers Deposit Bancorp, Inc.) Kentucky Mt. Vernon Bancshares, Inc. Kentucky The Bank of Mt. Vernon (a direct subsidiary of Mt. Vernon Bancshares, Inc.) Kentucky The Sabina Bank Ohio Ohio River Bank Ohio The Bank of Philippi West Virginia Boone County Bank West Virginia