Evaluations of 40 mass media programs/campaigns designed to influence cigarette smoking were reviewed. Information/motivation programs/campaigns generally produced changes in awareness, knowledge, and attitudes. Extensive national campaigns also produced meaningful behavioral change. Programs/campaigns designed to promote some specific smoking-related action produced mixed results, depending in large part on the type of promotion involved. Mass media cessation clinics were found to be effective, with media plus social support being more effective than viewing plus printed material, and either combination being more effective than viewing alone. It was concluded that mass media health promotion programs can be more effective than many academics may have thought, but that the knowledge necessary to ensure such success is seriously lacking. Research studies, rather than simple evaluations, are needed to improve our knowledge base and build a science of mass media health promotion.