 Treatment with varenicline reduces overall subjective cigarette craving and smoking reward in nicotine-dependent smokers. This preliminary study will explore the impact of varenicline treatment on smoking cue-induced craving and associated regional brain activation using BOLD fMRI. Twenty healthy smokers 10 males, 10 females will undergo two BOLD fMRI scans with the presentation of smoking-related and neutral cues at baseline and after five weeks of treatment with open-label varenicline. The investigators hypothesize that participants will report reduced urges to smoke on the Questionnaire of Smoking Urges-Brief and have less activation of the brain areas associated with craving during the fMRI after 5 weeks of varenicline and smoking cessation counseling compared to the baseline scan. 