Despite serious medical problems associated with smoking, 19% of adults in the U.S. continue to smoke. More than one-third of smokers attempt to quit each year, though most attempts end in relapse. People who try to quit often find treatment cost and availability are barriers to their success. We will test a novel cognitive retraining program implemented on a mobile device. The program retrains behavioral responses to smoking images in an attempt to modify brain circuits that control basic impulses to smoke. If successful, our research will provide a low-cost treatment option that can be widely distributed.