 The overarching goal of this line of research is to increase smoking abstinence rates using a combination of existing pharmacotherapies. The aim of the current study is to assess the safety and compliance as well as obtain preliminary estimates of efficacy and effect on craving and nicotine withdrawal of combination therapy with bupropion SR and varenicline. We will compare the efficacy estimates in this study with historical smoking abstinence rates with varenicline. To accomplish our aims, we will enroll 38 cigarette smokers in an open-label, phase II clinical trial. 