Some studies have shown that female smokers and smokers with a history of depression have an increased risk of relapse following smoking cessation treatment. This study examined the efficacy of bupropion sustained-release (SR) and the nicotine patch for smoking cessation in subgroups of smokers at possible risk for relapse. Data for this study were from a previously published randomized, double-blind, placebo-controlled clinical trial in which 893 smokers were randomized to four treatment conditions: placebo tablet + placebo patch, placebo tablet + 21 mg/24-hr nicotine patch, 300mg bupropion SR + placebo patch, and 300mg bupropion SR + 21 mg/24-hr nicotine patch. Study medication continued for 8 weeks after the quit day; brief individual cessation counseling was provided during weekly clinic visits. In comparison to the placebo tablet, bupropion SR approximately tripled 1-year non-smoking rates among women and previously depressed individuals. In contrast, the nicotine patch did not significantly improve cessation rates for any group. We conclude that bupropion SR is a first-line treatment for smoking that has the potential to benefit all smokers, especially women and the previously depressed.