A sense of purpose in life has been positively associated with mental health and well-being and has been negatively associated with alcohol use in correlational and longitudinal studies but has not been studied as a predictor of cocaine treatment outcome. This study examined pretreatment purpose in life as a predictor of response to a 30-day residential substance use treatment program among 154 participants with cocaine dependence. Purpose in life was unrelated to cocaine or alcohol use during the 6 months pretreatment. After controlling for age, baseline use, and depressive symptoms, purpose in life significantly (p < .01) predicted relapse to any use of cocaine and to alcohol and the number of days cocaine or alcohol was used in the 6 months after treatment. Findings suggest that increasing purpose in life may be an important aspect of treatment among cocaine-dependent patients.