The chronic and relapsing nature of substance abuse points to the need for continuing care after a primary phase of treatment. This article reviews the economic studies of continuing care, discusses research gaps, highlights some of the challenges of conducting rigorous economic evaluations of continuing care, and offers research guidelines and recommendations for future economic studies in this emerging field. Rigorous economic evaluations are needed by health care providers and policy makers to justify the allocation of scarce resources to continuing care interventions. The adoption of cost-effective continuing care services can reduce long-term consequences of addiction, thereby potentially increasing overall social welfare. (Contains 2 tables.)