The regulatory framework for Legionnaires' disease in France has undergone numerous changes in recent years. Since 1997, enhanced surveillance and efforts to improve case detection, diagnosis, and reporting have led to an increase in the system's sensitivity. Raising awareness among all public health surveillance partners, as well as media coverage of Legionnaires' disease—particularly during the 2003–2004 Pas-de-Calais outbreak—were likely key factors in improving this surveillance. Numerous initiatives were subsequently launched to combat this disease, notably through the government’s Legionnaires’ disease prevention plan, which aims to reduce its incidence by 50% by 2008. In this context, this article presents surveillance data on Legionnaires’ disease cases occurring during 2005.