Surveillance of listeriosis in France is carried out through mandatory reporting (DO) and the National Reference Center for Listeria (CNR) at the Listeria Laboratory of the Pasteur Institute, which centralizes and characterizes L. monocytogenes strains received from microbiology laboratories. The DO enables the physician at the Departmental Directorate of Health and Social Affairs (DDASS) to gather early information on patients’ dietary habits. Trends analyzed using CNR data available for 1998 (230 strains) and 1999 (244 strains) show no significant changes in incidence, the distribution of clinical forms, or the distribution of serotypes. The effectiveness of listeriosis surveillance in France has been strengthened by the introduction of the DO, which has improved the system’s responsiveness and the quality of available epidemiological data. This made it possible in 1999 to detect and investigate clusters of listeriosis cases and thus prevent the occurrence of full-scale epidemics.