OBJECTIVES: We investigated associations between tobacco industry denormalization attitudes and the smoking behavior of young adults (aged 18 to 29 years). METHODS: We analyzed data from 9455 young adults in the 2002 California Tobacco Survey. RESULTS: The data showed that 27.4% of young adults were "ever smokers" (smoked > or = 100 cigarettes in their lifetime), of whom 66.9% were current smokers (18.3% of young adults). Denormalization attitudes formed 2 major factors: support for anti-tobacco industry action and mistrust of tobacco companies. In multivariate logistic regression, support for action against the tobacco industry was negatively associated with current smoking (odds ratio [OR] = 0.16; 95% confidence interval [CI]=0.13, 0.19) and susceptibility to smoking, after we controlled for demographics, exposure to smokers, and advertising receptivity. Mistrust of tobacco companies was associated with smoking behavior, with anti-industry support acting as a mediating variable. Among current smokers, support for anti-tobacco industry action was strongly associated with intentions to quit (OR=4.64; 95% CI=3.15, 6.84) after we controlled for demographics, exposure to smokers, and advertising receptivity. CONCLUSIONS: Support for anti-tobacco industry action protects against smoking and is associated with intentions to quit among young adults. Encouraging involvement in tobacco control and against the tobacco industry may decrease smoking among young adults. (Author' s abstract)