Determining how adolescent smoking is affected by the rate of nicotine metabolism may help to identify individuals who are more susceptible to developing nicotine addiction. In addition, studying these effects in adolescent smokers can offer insight into the effects of nicotine metabolism on this crucial stage on the smoking continuum. For example, one might expect slower metabolizers to be less likely to progress to heavier, more dependent smoking because they retain nicotine longer, resulting in higher levels and potentially more adverse effects of nicotine. Conversely, faster metabolizers who clear nicotine quickly might be expected to smoke more cigarettes per day and to accelerate their smoking more quickly. The purpose of this study was to assess the effects of nicotine metabolism on cigarettes smoked per day and nicotine dependence in adolescent smokers. Based on adult smoking data, we hypothesized that faster metabolizers would smoke a greater numbers of cigarettes per day and would report higher levels of addiction.