Statewide evaluations of mental health services are colossal undertakings, reports of which are few in the published literature. Social workers are often called on to conduct program evaluations of both small- and large-scale mental health systems. A statewide evaluation system was implemented in the state of Georgia in 1999 to measure the impact of services on mental health, mental retardation, and substance abuse programs. This report delineates the evaluation of substance abuse services for the state of Georgia using the Addiction Severity Index. System-wide outcomes were assessed across 13 mental health regions, and 19 substance abuse programs participated. Consumers admitted to American Society of Addiction Medicine level II services were assessed at intake and 60 days posttreatment. Difficulties with the implementation of the statewide evaluation system, such as attrition, are identified and discussed. Recommendations for improving the evaluation system are also discussed. (Contains 1 table.)