OBJECTIVES:Cultural and sex differences in smoking rates among countries indicate different phases of the smoking epidemic. Their background is summarized in a four-stage model based on the Rogers Theory of Diffusion of Innovations. First, to test predictions of the Rogers theory and, second, to test whether, according to the theory, today's innovative process is smoking cessation, predicted by higher rates of cessation among the more highly educated and among men of all educational levels. METHODS:Data covered respondents older than 24 years from two Swiss Health Surveys (1997 and 2002). Logistic regression models were on lifetime smoking versus never-smoking, and on former smoking versus current smoking. RESULTS:Declining smoking rates in both sexes over time, measured by birth cohorts, indicate that the epidemic has peaked, but women of all educational levels and men of lower education still show high prevalence rates. The gap between higher-educated and lower-educated individuals is widening. CONCLUSION:Smoking prevalence is expected to decline further, particularly among women and little educated men. The incidence of tobacco-related diseases in women is predicted to exceed that of men, owing to their lower cessation rates.