In France, between 1974 and 1983, 1 194 diagnoses of L. icterohaemorrhagiae leptospirosis were confirmed serologically at Pasteur Institute (Paris), WHO Reference Center. The number of cases diagnosed each year rose from 74 in 1974 to 277 in 1983. The annual incidence in 1983 was 0.55 per 100 000. The temporal distribution shows that 25% of cases were in August and 63% between July and October. Two areas have a greater incidence: the South West and the East. The departments near the sea of the South East, the North and the West have the lowest incidence.