Introduction - An outbreak of acute gastroenteritis (AGE) occurs every winter in France and accounts for 700,000 to 3.7 million visits to primary care physicians. Here we present an overview and comparison of AGE epidemics that occurred in mainland France during the 2006/2007, 2007/2008, and 2008/2009 winter seasons. Method - Surveillance of AGE in France is carried out by several complementary systems: the Sentinelles Network for cases presenting to general practitioners, a network of hospital emergency departments, reports of clusters of AEFI through the reporting of nosocomial infections, mandatory reporting of collective foodborne illnesses, the National Reference Center for Enteric Viruses, and spontaneous reports by local authorities to the DDASS. Results - According to data from the Sentinelles Network, the 2006/2007 epidemic was moderate, the 2007/2008 epidemic was the earliest on record, and the epidemic curve for the 2008/2009 season had an unusual shape with a longer duration. There was a higher rate of emergency room visits in 2007–2008 and 2008–2009. In total, 491 clusters of GEA cases occurring over the three winter seasons were reported to the French Institute for Public Health Surveillance, with a gradual increase in the number of reported outbreaks from one season to the next. For the three seasons, approximately 60% of reports of GEA clusters originated from a nursing home, a long-term care facility, or a post-acute care and rehabilitation facility. A norovirus of genogroup II.4 was responsible for the vast majority of the 311 biologically confirmed clusters. The Bristol genotype was the most common during the first season, while genotypes 2006b and 2006a were the most common during the following two seasons. Discussion and Conclusion - The complementary surveillance systems for norovirus outbreaks in France show comparable trends and allow for effective characterization and comparison of winter outbreaks. The increase in reports of norovirus outbreaks could be explained by improved surveillance and the presence of new circulating norovirus variants. The implementation in the fall of 2010 of an application for recording clusters of GEA cases in nursing homes for the elderly (Ehpa) will allow for a more comprehensive and early identification of these outbreaks, enhanced investigations, and the rapid implementation of appropriate and effective management measures. (R.A.)