Despite the high prevalence of hepatitis C virus (HCV) infection among drug users enrolled in methadone maintenance treatment programs, few drug users are being treated with combination therapy. The most significant barrier to treatment is lack of access to comprehensive HCV-related care. We describe a pilot program to integrate care for HCV infection with substance abuse treatment in a setting of maintenance treatment with methadone. This on-site, multidisciplinary model of care includes comprehensive screening and treatment for HCV infection, assessment of eligibility, counseling with regard to substance abuse, psychiatric services, HCV support groups, directly observed therapy, and enhanced linkages to a tertiary care system for diagnostic procedures. Our approach has led to high levels of adherence, with liver biopsy and substantial rates of initiation of antiviral therapy. Two cases illustrate the successful application of this model to patients with HCV infection complicated by active substance abuse and psychiatric comorbidity.