The purpose of mandatory reporting (MR) of Legionnaires' disease is to monitor trends in the incidence of the disease, detect clusters of cases, and guide preventive measures. The Regional Health Agency, with support from the InVS Unit, investigates reported cases of Legionnaires' disease in the event of clusters and forwards the notification forms to the French Institute for Public Health Surveillance (InVS). This bulletin presents the results of Legionnaires' disease surveillance in Poitou-Charentes based on the notification forms received by the InVS through the end of 2012.