Cigarette smokers who quit on their own (n = 29) were compared with subjects from two commercial therapy programs: Aversion Group (n = 18) and Behavior Management Group (n = 16). Subjects were administered a Change-Process Questionnaire and a demographic and smoking-history questionnaire within seven weeks of successful cessation, then interviewed again in five months. Using a transtheoretical model of change developed by Prochaska (1979) six verbal and four behavioral processes of change and three stages of change (Decision to Change; Active Change; Maintenance) were analyzed. Subjects in each treatment group were middle class, heavy-smoking adults. The change-process analysis of cessation discriminated between the self-quitters and therapy quitters and between the two groups of therapy subjects on five variables. Stages of change interacted with the processes of change in the cessation of smoking behavior. Verbal processes were seen as important in making the decision to change while action processes were critical for breaking the actual smoking habit. Maintenance of cessation was related to, but not dependent on, how subjects actively changed smoking behavior.