Exercise holds potential to reduce substance use, but engaging patients in exercise regimens is challenging. Contingency management (CM) interventions can directly address adherence by targeting initiation and maintenance of exercise behavior. This study evaluated the efficacy of a CM-reinforced exercise intervention as an adjunct to standard outpatient substance use disorder treatment. Participants were 120 patients with substance use disorders who were randomly assigned to standard care with CM for completing exercise goals or CM for completing general nonexercise goals weekly for a 4-month treatment period. Urine samples were tested for evidence of illicit substance use up to twice a week during treatment and at follow-ups through month 12. Results found that the CM-exercise condition demonstrated during-treatment improvements on several physical activity and relevant psychosocial functioning indices (e.g., self-efficacy for exercise). The CM-exercise condition had no advantage relative to the CM-general condition in decreasing substance use. Overall, this study adds to a small body of well-powered trials assessing effects of exercise interventions as adjunct treatment for substance use disorders and finds no benefit over an alternate CM approach in terms of drug abstinence. (PsycINFO Database Record (c) 2020 APA, all rights reserved).