Motivational theories of drug use have assigned negative affect a central role in determining drug urges and drug relapse. The purpose of this study was to examine the effects of social stress on smoking urges in a controlled laboratory setting, and the relation of these responses to short-term (3-month) smoking cessation outcomes. Prior to a clinic-based smoking cessation program, 76 (64% female) smokers were assessed for their affective, cognitive, and physiological responses during the Borkovec social anxiety induction procedure. These responses were used to predict smoking urges immediately after the procedure and to predict abstinence at 3-month follow-up posttreatment. As expected, during the induction, urge to smoke was positively associated with anxiety ratings and negatively associated with self-efficacy to resist smoking. However, only heart rate increase and behavioral social skill (observed by independent judges) predicted smoking abstinence at 3 months. These results suggest that subjective affective and efficacy responses during a stressful social encounter are associated with smoking urges; however, urges and these responses may be related in different ways to the probability of smoking cessation.