The thesis, conducted as part of the E-care project, proposes a methodological process to facilitate the analysis and design of medical remote monitoring systems for early detection of signs of any complications. The proposed methodology is based on a multi-agent system using several types of ontologies associated with an expert system. The multi-agent system is suitable for medical monitoring with a distributed architecture to keep some autonomy and responsiveness of habitats. The process identifies the generic and specific aspects of each system. The designed architectures take into account all the patient data such as: patient profile, medical history, drug treatments, physiological and behavioral data, as well as data relating to patient's environment and his lifestyle. These architectures should be open to be adapted to new data sources.This methodology was applied to E-care project in order to define its information system. This information system is composed of two types of ontologies (problem ontology and several domain ontologies) and an expert system for the detection of risk situations. The problem ontology was built to manage the system including users and their tasks. Three domain ontologies have been built to represent, disease, drugs and cardiovascular risk factors. The expert system uses inference rules, which are defined in collaboration with medical experts using their knowledge and some medical guidelines. This methodology also defined the system architecture, which consists of four autonomous agents types namely: medical sensors to collect physiological measurements. The gateway collects data from sensors and transmits them from the patients' homes to the server. The server processes data and gives access to them. Finally the database secures storage of patient data.As part of the E-care project, an experiment was conducted to validate the various system components. This experiment has gone through two phases, the first was held at the University Hospital of Strasbourg, and the second is in the patients' homes.