The National Reference Center for Listeria participates in the epidemiological surveillance of human listeriosis in France by assessing the annual incidence of this infection and changes in the distribution of its various clinical forms, by detecting any abnormal increases in the number of cases, and by contributing to the study of foodborne transmission. Surveillance of listeriosis is conducted using strains sent primarily by hospital laboratory technicians (who accounted for 93% of strains in 1997) and by private laboratory technicians. This surveillance system is passive and therefore not exhaustive. The year 1997 was characterized by a number of sporadic cases of listeriosis very similar to that of 1996 (228 cases versus 220), confirming the decline observed over the past 5 years. The designation of listeriosis as a notifiable disease since March 1998 (Decree No. 98-169 of March 13, 1998, and Order of April 10, 1998) will provide two surveillance systems for this infection and allow for a better assessment of the characteristics of listeriosis in France. (adapted from the text)