The transdermal nicotine patch is the most widely used form of tobacco dependence treatment in the US and Europe. Yet, abstinence rates following patch treatment are only ~20% at 6-months and ~9% at 12-months. There is a growing recognition that nicotine dependence is a chronic disease, like asthma or diabetes, which requires maintenance therapy. While current guidelines established by the USDHHS's Public Health Service (PHS) recommend 8-week duration for transdermal nicotine therapy, support for this recommendation is limited. In a recent randomized placebo-controlled efficacy trial comparing standard (8-week) vs. extended (24-weeks) treatment with nicotine patches, we found that, at 24 weeks, point-prevalence abstinence rates were 30% in the 24-week arm vs. 20% in the standard therapy arm (p < .05); however, by week 52, 6 months after treatment was discontinued for the extended treatment arm, the quit rates were equivalent across the treatment arms. This was the first clinical trial to suggest that the benefits of extended treatment with transdermal nicotine are largely dependent on the continuation of active treatment. However, as an efficacy trial, this study was conducted under highly-controlled conditions with strict inclusion/exclusion criteria to enhance internal validity. If recommendations for the duration of nicotine patch therapy are to be formally revised to encourage maintenance therapy, these findings must be replicated and extended under "real-world circumstances" in an effectiveness trial. In addition, as done in clinical trials to support the use of methadone maintenance for opiate dependence, a replication study must include a treatment arm that receives maintenance therapy throughout the duration of the trial (52 weeks). Thus, we propose to conduct a randomized effectiveness trial to evaluate the benefits of maintenance therapy with transdermal nicotine patches for smoking cessation. Specifically, 540 smokers will receive brief counseling and will be randomized to: standard (8-weeks), extended (24-weeks), or maintenance (52 weeks) transdermal nicotine therapy. The primary outcome will be biochemically verified 7-day point prevalence abstinence at week 52. Additional study aims include assessing: 1) treatment side effects across study arms; 2) longitudinal patterns of relapse and recovery across treatment arms; 3) mediators and moderators of treatment effects; and 4) cost-effectiveness. Overall, the trial findings will provide critical data for future PHS reviews of maintenance therapy with transdermal nicotine for subsequent treatment guidelines; for third-party payer assessments of maintenance transdermal nicotine as a covered benefit; and for individual smokers' decisions to use maintenance transdermal nicotine through over-the-counter access. In turn, this study may help to attain the Healthy People 2010 goals of reducing the US rate of tobacco use.