The prevalence of smoking among college students is surprisingly high and represents a significant public health issue. However, there are few longitudinal studies of smoking in this population. This study examined the prevalence and predictors of transitions in smoking behavior among a cohort of 548 college students. Over the course of 4 years, 87% of daily smokers and almost 50% of occasional smokers continued to smoke. Among nonsmokers, 11.5% began smoking occasionally and none became daily smokers. In general, predictors of smoking behavior change were significant only among baseline occasional smokers and included gender, smoking outcome expectancies, and affect regulation expectations. Peer and parental smoking, demographics, affect, stress, and alcohol use were generally not predictive of change. Tobacco control interventions targeted at college students are clearly warranted.