This evaluative study examined the impact of recreational therapy interventions on intrinsic motivation and holistic functioning among adults at a substance use treatment facility. West (2001) identified motivation as a key variable in treating substance use disorders, and self-determination theory, specifically intrinsic motivation, provided a useful framework for this study. Intrinsic motivation is grounded in self-determination theory and defines various motivation types and how to increase participants' engagement. Holistic functioning is another tool in assessing a participant's recovery. For this evaluation, four domains were specifically assessed: (a) physical, (b) leisure, (c) social, and (d) daily living functioning. These quality of life components are affected heavily during prolonged substance use. Results suggest that recreational therapy interventions utilizing a self-determination framework improves participants' intrinsic motivation and holistic functioning in a substance use treatment setting.