Objectives. This study examined the changes in smoking initiation and cessation needed to realize the Healthy People 2010 national adult smoking prevalence objective (13%). Methods. Using data fi om the National Health Interview Surveys, we calculated smoking prevalence over time with a dynamic population demographics model, examining the effects of changes in smoking initiation and cessation. Results. The draft objective is unattainable solely through decreases in smoking initiation. It could be achieved through smoking cessation alone only if cessation rates immediately increased by a factor of more than 3.5. Assuming plausible decreases in initiation and increases in cessation, the draft objective is virtually unattainable. Conclusions. The health objectives should challenge the status quo but be achievable. Formal analysis often can assist in establishing reasonable objectives.