Recent emphases on increasing accountability, using less intensive settings, and implementing evidence-based services helped to focus the research community on the structure, processes, and outcomes of services delivered to substance abuse clients. Considerably less attention has been given to understanding how to structure services to enhance engagement and retention leading to treatment continuity. This study examined structural characteristics of community-based treatment facilities in relationship to the availability of supportive services within a sample of 1,332 substance abuse treatment programs surveyed through the Alcohol and Drug Services Study in 1996 and 1997. Structural and client characteristics are important predictors of added supportive services. Furthermore, a program with a broader and established set of core services is more likely to have expanded supportive services. These findings have implications for public health professionals, both in terms of ensuring sustainable service programming for these chronic clients and in identifying services to adopt or discard to meet a population with multiple needs.