The RIMED study (Ionizing Radiation in the Medical Field) aimed to establish an epidemiological surveillance system for healthcare workers exposed to ionizing radiation in order to better monitor the health risks specific to this population. The primary objective of the pilot study presented here is to analyze the feasibility of establishing a cohort of healthcare workers based on a sample of hospitals in order to study mortality by cause in this population according to its socio-professional characteristics (department of assignment, profession, etc.). Seven hospitals were selected for this feasibility study. Every individual present in one of these hospitals who was monitored by a personal dosimeter prior to December 31, 2003, was to be included in the RIMED cohort. A total of 5,126 subjects were included based on data from the Information System for the Surveillance of Exposure to Ionizing Radiation (SISERI), a database created and managed by the Institute for Radiation Protection and Nuclear Safety (IRSN), supplemented by information obtained from the occupational health services of the relevant institutions. The information needed to determine vital status and causes of death could be obtained for only 38% of the subjects. This study showed that in 2004, a surveillance system for medical and paramedical personnel exposed to ionizing radiation—based on SISERI data, supplemented by data from hospital occupational health services—could not be established in an operational manner and did not allow the set objectives to be met. To implement such monitoring, it will be necessary to wait until SISERI becomes operational, while recommending that employers systematically and mandatorily submit certain personal data (date of birth, etc.) or professional data (department of assignment, profession, etc.). SISERI could then serve as the sole database for conducting epidemiological surveillance of medical and paramedical personnel exposed to ionizing radiation. (R.A.)