Middlefield Banc Corp. operates as the bank holding company for The Middlefield Banking Company that provides various commercial banking services to small and medium-sized businesses, professionals, small business owners, and retail customers in northeastern and central Ohio. It accepts checking, savings, negotiable order of withdrawal, and money market accounts, as well as time certificates of deposit and IRA accounts. The company offers operational and working capital, term business, residential construction, professional, and residential and mortgage loans, as well as consumer installment loans for home improvements, automobiles, boats, and other personal expenditures; loans to finance capital purchases; selected guaranteed or subsidized loan programs for small businesses; and agricultural loans. It also provides safe deposit facilities, travelers' and official checks, money orders, and ATM services; online banking and bill payment services to individuals; and online cash management