 This application proposes to conduct a fully-powered, multisite trial of the HARP program. A total of 400 individuals with serious mental illnesses and one or more chronic medical condition will be recruited from three diverse community mental health clinics in the Atlanta metro region and randomized to the HARP program or usual care. For individuals in the HARP program, two peer educators with SMI and one or more chronic medical condition will lead a six-session, six-week manualized intervention, which helps participants become more effective managers of their chronic illnesses. Follow-up interviews and chart reviews at 3 months, 6 months and one year will assess changes in clinical outcomes, improvement in generic and disease-specific measures of illness self-management, and quality of care. During the final phase of the study, a dissemination strategy building on the CDSMP training infrastructure will allow program participants to lead HARP groups. 