Understanding the role of motivation in substance abusers' acceptance of treatment is critically important to improving treatment outcomes. To examine this phenomenon a cohort of substance abuse treatment clients was recruited from two treatment programs whose services are funded by a state managed care system. Motivation at treatment entry was examined. Better motivation was consistently associated with severity of substance use. Neither the coercion that accompanies legal system involvement nor self-referral was significantly related to measured levels of motivation. Motivation was not related to alcohol and drug use severity six months later. The severity associated with motivation at treatment entry was, for the most part, not related to clients' success six months later. Implications for social work practice with substance abusers are discussed.