Surveillance activities first target health problems for which treatment, effective prevention or control measures are available. The data produced by surveillance systems allow prioritising public health actions and defining the objectives of infectious diseases control or prevention. The surveillance of infectious diseases relies on a large number of partners grouped in a public health network in which clinicians have a prominent role. In France, the surveillance of infectious diseases is based on mandatory notification of some diseases, national reference centers, networks of voluntary health professionals and repeated surveys, alerting health authorities in case of threats and identifying the determinants of changes in the population health's status. At hospital, the infectious risk is significant and the risk of epidemic outbreaks very high. A solid system for surveillance is mandatory. An educational program is needed to define the prevention program based on the use of hand disinfection and other standard precautions, antiviral and pneumococcal vaccination. A strong cooperation between general practitioners, healthcare team and relatives is necessary.