The transdermal nicotine patch is the most widely used form of tobacco dependence treatment in the US and Europe, but most smokers are unable to successfully quit with this form of treatment. Failure to respond to this treatment may, to a large extent, be due to the use of nicotine patches for only 8 weeks, the recommended treatment duration. We have found in a controlled randomized clinical trial that using the nicotine patch for 24 weeks can increase quit rates significantly. We propose here a clinical trial to replicate and extend these results to a community setting in the real-world, using the same research design utilized in clinical trials to demonstrate the effectiveness of methadone maintenance therapy for opiate dependence. Specifically, 540 smokers will receive counseling and standard (8-weeks), extended (24-weeks), or maintenance (52 weeks) therapy with transdermal nicotine patches. The main outcome is biochemically-verified smoking cessation at week 52. The cost-effectiveness, safety, and mechanism of effect (e.g., promotion of recovery following a lapse) for maintenance therapy with transdermal nicotine will also be assessed. The study results may change how we treat nicotine dependence with transdermal nicotine.