Twenty of sixty volunteers for smoking cessation were assigned to single-session hypnosis, 20 to a placebo control condition, and 20 to a no-treatment control condition. The single-session hypnosis group smoked significantly less cigarettes and were significantly more abstinent than a placebo control group and a no treatment control group at posttest, and 4-week, 12-week, 24-week and 48-week follow-ups.