Computers have the ability to process and access tremendous amounts of information in our daily lives. But, now, individuals have this ability by carrying a smart card in their own wallets. These cards provide us the versatility, power, and security of computers. This study begins with a short description of smart cards and their advantages. Then, an electronic circuit that is designed for healthcare application in hospitals is introduced. This circuit functions as a smart card holder identifier, access controller for hospital doors and also can be used as a smart card reader/writer. Design steps of this electronic circuit, operation principles, serial communication with P.C., and the software are examined. Finally a complete access control network for hospital doors that functions with smart cards is discussed.