This article presents the missions and activities of the Unit for Nutritional Surveillance and Epidemiology (USEN), established in 2000 through an agreement between the InVS and the Ista (Scientific and Technical Institute for Nutrition and Food) of the CNAM. USEN’s initial work focused on folate status and intake among adults, iodine status, and the prevalence of obesity among children aged 7 to 9. The authors also present the INCA-2/ENNS survey project (National Individual Food Consumption Survey/National Nutrition and Health Survey), which is scheduled to begin in early 2004.