Surveillance of Legionnaires' disease in France is primarily based on a mandatory reporting system. The system, which has been in place since 1987, was improved through various measures in 1997... At the European level, France actively participates in the EWGLI network. This network, which includes 31 countries, reports to the health authorities of the country concerned any case of Legionnaires' disease involving a traveler who traveled during the 10 days preceding the onset of the illness, specifying the locations visited. Surveillance of Legionnaires' disease is based on collaboration between clinicians, microbiologists, and public health physicians. It is therefore important to promote the use of urinary antigen detection tests as well as the submission of strains to the CNR.