In 2001, 807 cases of Legionnaires" disease were reported to the Institut de veille sanitaire (French national public health centre). The incidence of the disease was 1.35 cases per 100,000 inhabitants, compared to a mean European incidence of 0,6 per 100,000. The median age was 59 years [16-97], the group aged more than 80 being the most affected. The sex ratio M/W was 3.1. The outcome of the disease was known in 69% of all cases, the case fatality ratio rating 19.9%. Among the contributing factors found in 558 cases, 11% had a cancer or blood disease, 12% received an immunosuppressant treatment, 10% were diabetic and 40% were smokers. In 2001, 13% (105/807) cases stayed in a hospital or a clinic during the incubation period, compared to 20% in 2000, and 11% were travel-associated.