Data on smoking prevalence since 1974 are presented for the United States, Canada, Great Britain, Australia, Norway and Sweden. During this period, sex-specific prevalence has decreased in all the countries studied, with the exception of Norway, where women showed an increase. There was also a considerable decline in uptake of smoking by the young over this period, suggesting that the observed decline in prevalence is likely to continue. In the United States, the rate of decline in adult smoking prevalence has been linear. This linear pattern is probably similar in prevalence in most other countries studied, with the notable exception of Australia, which demonstrated no change for the majority of the period. Among the six countries studied, the United States had neither the lowest smoking prevalence nor the fastest rate of decline over the period. Differential patterns of change infer that the successful public health interventions in some countries are not being applied in others. While the lack of change in Australia prior to 1983 is surprising, this was followed by a sizable drop in smoking prevalence for both higher and lower educational groups in conjunction with the introduction of mass media-led antismoking campaigns. Most of the other countries report an ever increasing gap in prevalence between higher and lower educational groups. These findings suggest that all countries might benefit from a greater exchange of antismoking ideas and public health action.