In 2013, 207 cases of Legionnaires' disease were reported in the Rhône-Alpes region through the surveillance system for notifiable diseases (MDO). As in previous years, the incidence rate of reported cases in Rhône-Alpes (3.2 cases per 100,000 inhabitants) remains higher than the national rate (1.9 cases per 100,000 inhabitants). Although variations are observed at the departmental level, this incidence rate has remained stable at the regional level over the past 5 years. Case characteristics and risk factors are comparable to national trends, except for a lower case fatality rate in Rhône-Alpes (7.7% versus 12.2%, p<0.05). In the majority of confirmed cases (99%), the initial diagnosis was based on a urinary antigen detection test. Among the 207 cases, a strain was isolated in 61 of them (30% versus 26% nationally). Ten clusters of cases (ranging from 2 to 8 cases) were identified and investigated in the region in 2013. Although these investigations did not definitively identify sources of contamination, they triggered the implementation of control and management measures at suspected sources of contamination to reduce the occurrence of further cases. As a reminder: Legionella bacteria can be isolated from a lower respiratory tract specimen, but sputum is usually sufficient. Culture is strongly recommended when Legionnaires’ disease is diagnosed via a positive urinary antigen test. Genotyping allows for the identification or confirmation of suspected clusters and helps pinpoint the source of contamination.