Because of the multifaceted, chronic, and relapsing nature of substance use disorders, case management has been adapted to work with persons who have these disorders. Deliberate implementation has been identified as a powerful determinant of successful case management. This article focuses on six key questions about implementation of case management services on the basis of a comparison of experiences from the United States, the Netherlands, and Belgium. It was found that case management has been applied in various populations with substance use disorders, and distinct models have been associated with positive effects, such as increased treatment participation and retention, greater use of services, and beneficial drug-related outcomes. Program fidelity, robust implementation, extensive training and supervision, administrative support, a team approach, integration in a comprehensive network of services, and minimal continuity have all been linked to successful implementation.