In total, 70 smokers will be randomized to: varenicline alone (an FDA-approved smoking cessation medication) or varenicline plus contingency management (CM) (a behavioral procedure with rewards for target behaviors, like smoking abstinence). Patients in both conditions will receive varenicline for 12 weeks with standard smoking cessation therapy and regular breath and urine sample monitoring for smoking. Patients assigned to CM will earn chances to win prizes for each breath sample that tests negative for smoking, and urine samples that test negative for smoking will result in even greater chances for prizes. More CM patients are expected to achieve and maintain abstinence than patients receiving varenicline alone.