Since surveillance was strengthened in 1997, the number of reported cases of Legionnaires' disease has continued to rise. This increase reflects efforts to improve case detection and diagnosis, as well as the significant involvement of reporting entities. At the same time, raising awareness among all public health surveillance partners and media coverage of Legionnaires' disease—particularly during community outbreaks—have likely been key factors in improving policies to prevent risks associated with Legionella. Following the 2003–2004 Pas-de-Calais outbreak—the largest known Legionnaires’ disease outbreak in France—two circulars were issued: the first in February 2004 requiring government agencies in each department to conduct a census of wet-type cooling towers (TAR), and the second in December 2004 specifying the regulations for the inspection of all wet-type cooling towers. Against this evolving epidemiological and regulatory backdrop, this article presents surveillance data on cases of Legionnaires' disease that occurred during 2004.