 Subjects will be recruited from prenatal clinics that serve primarily a low-income, minority population. Two hundred sixty-eight pregnant smokers will be randomly assigned to receive smoking cessation behavioral counseling and either a 6-week course of mint flavored placebo or nicotine gum, followed by 6 weeks of decreasing doses. Maternal blood for genotyping will be obtained at study entry. Primary outcome measures will be 7-day point prevalence of cigarette abstinence, number of cigarettes smoked per day, urinary cotinine concentrations, and measures of tobacco exposure i.e., carbon monoxide in exhaled air and urine anabasine and anatabine at 6 weeks after the quit date and at 32-34 weeks gestation, and infant birth weight. We hypothesize that: 