This study examines the feasibility of integrated treatment for hepatitis C in active IDUs using a client-centered, multidisciplinary model that combines expert care in five domains: (a) antiviral pharmacotherapy for HCV infection; (b) substance abuse treatment; (c) psychiatric evaluation and treatment; (d) primary medical care; and (e) intensive, client-centered, case management. The Weill Cornell Medical College Center for the Study of Hepatitis C collaborates with community-based organizations providing services to injection drug users to provide multidisciplinary, integrated care using a model that combines the resources of culturally appropriate community-based agencies with those of a state-of-the-art tertiary care center.