The continuously increased mobility of patients and doctors, in conjunction with the existence of medical groups consisting of private doctors, general practitioners, hospitals, medical centers, and insurance companies, pose significant difficulties on the management of patients' medical data. Inevitably this affects the quality of the health care services provided. The evolving smart card technology can be utilized for the implementation of a secure portable electronic medical record, carried by the patient herself/himself. In addition to the medical data, insurance information can be stored in the smart card thus facilitating the creation of an "intelligent system" supporting the efficient management of patient's data. In this paper we present the main architectural and functional characteristics of such a system. We also highlight how the security features offered by smart cards can be exploited in order to ensure confidentiality and integrity of the medical data stored in the patient cards.