ICRP publication 73 (Radiological Protection and Safety in Medicine) introduced the concept of "diagnostic reference levels" (DRL), for medical exposures specifically. Because dose limits should not be applied for diagnostic or therapeutic irradiation, the approach to radiological protection is slightly different from that in occupational or public exposures. Reference levels, that are neither optimum levels, nor dose limits, are a tool for optimisation. DRL are set for standard procedures, for groups of patients or standard phantom and not for special exposures and individual patients. They act as a test for identifying situations where patient doses are becoming unusually high and local review of procedures and equipment is required. Within the framework of implementation of Directive 97/43, the Health Directorate entrusted its radiation protection agency (past OPRI, at present time DGSNR and IRSN) to determine the national reference dose levels in diagnostic radiology in close cooperation with relevant scientific and professional societies. The pragmatic way, recommended by European Commission, to assess DRL values is to use the third quartile values observed in wide scale surveys of typical doses for common procedures. In the absence of recent and wide-ranging data for France, in a first step, European DRL have been adopted as starting points. To go further, a campaign of patient dose measurements has been launched by a steering committee (OPRI, SFR and SFPM) to allow the actual establishment of national reference values and to prepare their periodic review in a continuous process of optimization. © 2003 EDP Sciences.