Prochaska and DiClemente's (1984) cyclic-stage model of self-initiated smoking cessation divides the cessation process into five stages. This model was applied to a young adult population to determine the cross-sectional distribution of stages and the frequency and pattern of changes among stages over time. Compared to older adults, the distribution of the stages differed substantially: There were twice as many relapsers and only half as many maintainers among young adults. One-year changes in stages were examined using a static model, which did not take into account the cyclic nature of the change process, and a more realistic dynamic model, which did. Both models, especially the dynamic model, suggested substantially more movement among stages in younger than in older adults.