Heavy smokers (N = 408, smoking more than 25 cigarettes/day) were randomized to receive high-dose (25 mg) or standard-dose (15 mg) nicotine patch therapy delivered during the daytime only (16 hr) for a period of 6 weeks. Treatment effects of each dose were similar. The percentages of participants not smoking at 2-, 6-, and 12-month follow-ups were 26 versus 20, 14 versus 16, and 14 versus 14 for the 15-mg and 25-mg doses, respectively. The higher dose was well tolerated, and adverse event profiles for both treatment doses were very similar. Stepwise Cox proportional hazards analyses indicated that initial postrandomization craving and baseline scores on the Center for Epidemiological Studies Depression Instrument predicted time-to-relapse during treatment; only initial craving predicted relapse over the entire study interval (12 months). The results of this trial do not support the routine use of higher dose nicotine patch therapy in the treatment of nicotine dependence.