Influenza surveillance began in Mayotte in June 2009 during the 2009 influenza A(H1N1) epidemic, with the aim of describing the seasonal patterns of influenza on the island, rapidly detecting any unusual trends, and documenting the circulation of influenza viruses.This surveillance relies on a network of sentinel physicians, consisting of 15 doctors spread across the island: 7 private general practitioners, 7 doctors from the hospital center’s (CHM) outpatient clinics, and one doctor from Médecins du Monde. They report the weekly percentage of their consultations dedicated to patients presenting with influenza-like illness. When influenza activity increases, the CHM sentinel physicians are asked to collect a nasopharyngeal swab from two patients with flu-like symptoms per week for influenza virus detection via PCR. Laboratory tests are performed by the CHM laboratory. Surveillance of influenza activity in outpatient settings is supplemented by monitoring the daily number of emergency department visits and the reasons for consultation (Oscour® surveillance), as well as by tracking the weekly distribution of antipyretics (paracetamol and ibuprofen®) through a network of 7 sentinel pharmacies.