This study was designed to assess the effect of hypnotic and nonhypnotic suggestion for smoking cessation or reduction in smoking. In addition, the study assessed whether hypnotizability, motivation to stop smoking and locus of control orientation were predictive of outcome. Research concerned with stop smoking programs, locus of control studies and the debate concerning the nature of hypnosis was reviewed. Eighty-four subjects were assigned to five conditions. These conditions allowed comparison of an hypnotic induction procedure against a suggestion/no hypnosis procedure. These procedures were presented in both the active and passive voice. Saliva thiocyanate was used as a biochemical measure of smoking behavior. No significant difference in smoking reduction was found between treatments using an induction procedure and those using suggestion/no induction or between active and passive instructions. In addition, there was no significant difference in the success rate between the four treatment conditions combined and a no treatment control group. Subjects in all groups, including the controls, showed a substantial reduction in smoking. Subjects with an internal locus of control orientation were no more successful than those with an external orientation at reducing smoking. Hypnotizability also failed to predict treatment outcome. How much subjects liked to smoke was the best predictor of failure to reduce smoking.