The California Department of Health Services conducted a $28,600,000 tobacco education media campaign in 1990 and 1991. An independent evaluation of the media campaign featured four waves of data-gathering, one prior to the campaign's beginning and three at intervals thereafter. In all, 29,264 students in grades 4-12 and 6,785 adult smokers provided data for the evaluation. Through telephone interviews for adults and written questionnaires for students, these participants supplied information so that each person could be classified as exposed or unexposed to the media campaign's advertisements. Five criterion variables were used in the evaluation: campaign awareness, tobacco use, smokers' intention to quit, nonsmokers' intention to start, and attitudes toward smoking. Based chiefly on the differences between the results of waves 1 and 4, we believe the media campaign had a number of positive effects on California students. For adult smokers, the results were mixed.