OBJECTIVE: This study examined the relation of smoking and medical history, social support, and hypnotizability to outcome of a smoking cessation program. METHOD: A consecutive series of 226 smokers referred for the smoking cessation program were treated with a single-session habit restructuring intervention involving self-hypnosis. They were then followed up for 2 years. Total abstinence from smoking after the intervention was the criterion for successful outcome. RESULTS: Fifty- two percent of the study group achieved complete smoking abstinence 1 week after the intervention; 23% maintained their abstinence for 2 years. Hypnotizability and having been previously able to quit smoking for at least a month significantly predicted the initiation of abstinence. Hypnotizability and living with a significant other person predicted 2-year maintenance of treatment response. CONCLUSIONS: These results, while modest, are superior to those of spontaneous efforts to stop smoking. Furthermore, they suggest that it is possible to predict which patients are most likely and which are least likely to respond to such brief smoking cessation interventions.