To determine if RJR Nabisco's cartoon-theme advertising is more effective in promoting Camel cigarettes to children or to adults. To determine if children see, remember, and are influenced by cigarette advertising. Use of four standard marketing measures to compare the effects of Camel's Old Joe cartoon advertising on children and adults. High school students, grades 9 through 12, from five regions of the United States, and adults, aged 21 years and over, from Massachusetts. Recognition of Camel's Old Joe cartoon character, product and brand name recall, brand preference, appeal of advertising themes. Children were more likely to report prior exposure to the Old Joe cartoon character (97.7% vs 72.2%; P less than .0001). Children were better able to identify the type of product being advertised (97.5% vs 67.0%; P less than .0001) and the the Camel cigarette brand name (93.6% vs 57.7%; P less than .0001). Children also found the Camel cigarette advertisements more appealing (P less than .0001). Camel's share of the illegal children's cigarette market segment has increased from 0.5% to 32.8%, representing sales estimated at $476 million per year. Old Joe Camel cartoon advertisements are far more successful at marketing Camel cigarettes to children than to adults. This finding is consistent with tobacco industry documents that indicate that a major function of tobacco advertising is to promote and maintain tobacco addiction among children.