Cigarette smoking causes significant morbidity and mortality in the United States. Smoking cessation is difficult, with the average smoker attempting to quit five times before permanent success. Moreover, the majority of smoking quit attempts result in relapse. Brain stimulation for smoke cessation is an exciting new area that builds on advancing neuroscience knowledge concerning the functional neurocircuitry of addiction. Cortical stimulation can now be performed non-invasively by transcranial magnetic stimulation (TMS). A few studies have shown that TMS can reduce cue-elicited craving in smokers. Previous research by our group has shown that a single session of 15 minutes high frequency (10 Hz) repetitive TMS (rTMS) at 100% motor threshold over the left dorsal lateral prefrontal cortex (an area that is likely involved in inhibiting craving) can reduce cue-induced craving compared to sham TMS. However, methodological concerns surrounding these preliminary findings limit definitive conclusions about the effectiveness of TMS over a longer period of time. This R21 proposal will integrate more rigorous experimental conditions, a true double-blind methodology, MRI guided stimulation site and a longer-term follow-up assessment. Using rigorous double-masked methods and MRI guided stimulation site, we propose that using active rTMS or sham rTMS, to determine whether 10 sessions over a two week period consisting of 15 minute high frequency rTMS can reduce cue-induced craving and cigarette consumption for cigarette smokers. The project will also optimize rational rTMS parameters to make TMS to an efficacious treatment for nicotine dependence. In the two years of project, we plan to recruit 42 treatment-seeking nicotine-dependent cigarette smokers, both males and females of all ethnic and racial groups between the ages of 18 and 60 to participate in the study. The 42 participants will be randomly assigned to receive active prefrontal TMS or sham prefrontal TMS. The data from this R21 will provide the information needed for launching a definitive larger-scale investigation into potential clinical applications of TMS in smoke cessation. The results from this pilot will also likely supply substantial information about the utility of cortical stimulation for smoke cessation.