In 3 studies, the authors developed and began to validate a measure of the propensity to act rashly in response to positive affective states (positive urgency). In Study 1, they developed a content-valid 14-item scale, showed that the measure was unidimensional, and showed that positive urgency was distinct from impulsivity-like constructs identified in 2 models of impulsive behavior. In Study 2, they showed that positive urgency explained variance in risky behavior not explained by measures of other impulsivity-like constructs, differentially explained positive mood-based risky behavior, differentiated individuals at risk for problem gambling from those not at risk, and interacted with drinking motives and expectancies as predicted to explain problem drinking behavior. In Study 3, they confirmed the hypothesis that positive urgency differentiated alcoholics from both eating-disordered and control individuals.