Introduction - Influenza surveillance is a major public health issue because it can have a significant impact on the population. In France, this surveillance is based on the Sentinelles Network, the Grog, and the National Reference Centers dedicated to influenza. Furthermore, since 2004, the French Institute for Public Health Surveillance (InVS) has been operating a syndromic surveillance network based on emergency departments, SOS Médecins, and mortality data, with the goal of providing continuous, sensitive, and non-specific health surveillance. This article describes the limitations and benefits of such a system during the surveillance of the 2009 influenza A(H1N1) epidemic. Method - Individual data were recorded from the 250 emergency departments, 55 SOS Médecins associations, and 1,000 computerized civil registry offices comprising the Sursaud® syndromic surveillance system between 2008 and 2010. A description of the epidemic’s dynamics and an analysis by age group were conducted for the first two data sources. Mortality surveillance was based on the weekly number of deaths per 100,000 inhabitants. Results—Analysis of influenza data from the Sursaud® system allowed for precise tracking of the epidemic’s progression. Its impact on the population is evident between weeks 35 of 2009 and 01 of 2010 based on activity in emergency departments or SOS Médecins, with younger age groups more frequently affected; the impact on mortality remains very limited. Discussion - The description of the influenza epidemic based on syndromic surveillance data is consistent with that obtained by other surveillance networks. The trend by age group is also consistent with what has been observed internationally. Syndromic surveillance proves to be a valuable addition to influenza surveillance, thanks to the provision of data on patients’ ages and geographic locations, as well as the responsiveness of this method. (R.A.)