A seventh-grade program based on social psychological theories attempted to prevent non-smokers from starting to smoke. Two competing strategies, a Short-Term Influences Curriculum and a Long-Term Influences Curriculum were compared. Within these broad strategies, several other variables were also tested: the use of same age peer opinion leaders or health educators as teachers, the use of media supplements and the elicitation of a public commitment not to become a regular smoker. Program effectiveness was evaluated using self-report measures confirmed by saliva thiocyanate analyses. The treatment groups were compared to a standard curriculum comparison group.