The smart cards are considered as "intermittently connected devices" ensuring the security and the confidentiality of the data. This technique can be used in the healthcare domain for 2 types of applications: 1. patient cards for administrative functions (Social Security card, identification card) or medical purposes (general medical record or "niche" cards); 2. healthcare professionals cards for identification, authentification of the bearers. Electronic signature and cryptography algorithms reinforce the security of the transactions in medical informatics and telematics. In every case, the smart card must be considered as a mobile tool, intermittently connected with a larger, not limited information system.