Perceptions of the health risks associated with smoking in comparison with not smoking were assessed for the self and the "typical smoker" among four groups of adults: current, former and nonsmokers in the community, and smokers who had joined cessation clinics to help them quit. Comparisons across groups indicated that risk perceptions differed as a function of smoking status. Clinic attendees reported the highest smoking risk and the greatest perceived benefit of not smoking, and community smokers reported the lowest of each. In addition, community smokers were the only group to exhibit an "optimistic bias" (i.e., a perception that they were less vulnerable to health risk than was the typical smoker). Results from this cross-sectional study suggest that the decision to engage in and to stop risky behaviors is related to the perceptions of the health risk associated with those behaviors.