To meet the health needs of adolescents 16 to 19, two Swiss cantons have largely modified their school health systems: this paper describes two programs located in the French speaking part of Switzerland that include both screening and educational activities. These activities are run on an collective and individual basis by specially trained nurses and physicians. Three conditions appear essential for the effectiveness of such programs: priorities should be derived from the needs as expressed by the adolescents themselves. The system should be able to adapt constantly to new problems as soon as they are detected. All activities should be carefully evaluated.