Thanks to high vaccination coverage and very high vaccine efficacy, pertussis primarily affects infants too young to receive the vaccine, as well as adolescents and adults whose immunity acquired through previous infection or vaccination has waned. The disease remains severe in infants, which led in April 1996 to the resumption of surveillance—which had been discontinued in 1986—through a metropolitan pediatric hospital network. Its objective is to monitor the evolution of severe forms of pertussis in children and to assess the impact of changes in vaccination strategy on the epidemiology of the disease. This article presents the results of the surveillance conducted by this network in 2002. (R.A.)