A randomized double-blind, active controlled, parallel group, multi-center phase II clinical trial was conducted to evaluate the efficacy of reduced-nicotine cigarettes as a novel smoking cessation treatment (under Investigational Device Exemption 69,185). The concept for a reduced-nicotine cigarette designed to progressively wean smokers from the smoking habit is based on research demonstrating that successful smoking cessation is not only dependent on withdrawal of nicotine, but also on weaning from the habitual sensory and behavioral reinforcement of smoking. Treatment consisted of Quest brand of cigarettes (Quest 1, 2, and 3), which respectively deliver 0.59+/-0.06, 0.3+/-0.05, and less than 0.05 mg nicotine, either alone or in combination with nicotine replacement therapy (NRT). The primary endpoint was 4 weeks of continuous abstinence (Weeks 7-10), with additional follow-up at 3 and 6 months. Adult men and women smokers (N = 346), motivated to quit, were randomized to one of three treatment groups: Quest plus NRT (NRT pretreatment 2 weeks before, and NRT after the quit date), Quest plus placebo patch, or active control plus NRT (conventional cigarette, followed by NRT after quit date). Results showed that Quest plus NRT was more effective than active control plus NRT in achieving 4 weeks of continuous abstinence (32.8% vs. 21.9%). Quest plus placebo patch yielded an abstinence rate similar to that of the active control plus NRT (16.4% vs. 21.9%). No serious adverse events were attributable to the investigational product. Quest plus NRT offers promise as a new smoking cessation treatment.