The aim of this study was to examine the relationship between cessation and age at which person starts smoking. Data from a survey of nine neighborhoods in Philadelphia (1985-1987) were analyzed. Interviews were conducted in the home using a structured questionnaire. Participants were from a probability sample (n = 1,700) of males aged 35 years or older. Sixty-six percent of the smokers in this series started smoking before 18 years of age. Smoking cessation rate was 58.1% in Whites and 38.8% in Blacks. Age, race, marital status, education, health condition, amount smoked, and duration of smoking were significant predictors of smoking cessation. Age at initiation of smoking was a significant factor for continuation of smoking. Men who started smoking before 16 years of age had an odds ratio of 2.1 (95% confidence interval: 1.4-3.0) for not quitting smoking compared to those who started at a later age. These findings emphasize the need for prevention program targeted to children below 16 years of age.