The Postgraduate Center for Mental Health (PCMH) of New York City will serve persons with serious mental illness and co-occurring opiod use disorders, embedding Medication-Assisted Treatment within two psychiatric clinics that currently provide individual and group-based psychosocial treatment, motivational enhancement strategies, trauma-informed cognitive-behavioral therapy, psychiatric care, harm reduction, and peer support. A Collaborative Care Team of Psychiatric Nurse Practitioner/Prescriber, Nurse Care Manager, Co-Occurring Disorders Clinician, and Peer Outreach Staff will provide comprehensive services using the office-based model of MAT and shared appointments for clients enrolled in successive cohorts of twenty. All MAT clients will be enrolled in the PCMH Care Coordination Medical Home program, and project staff will use the NYSW ISTOP-PMP, consultation with primary providers, toxicology screens, and patient education to reduce risks of harm and diversion. Persons served will be Medicaid/Medicare-eligible, and demographics include 48% African-American, 22% White, 28% Latino, and 2% Asian. All clients will have a diagnoses of serious mental illness. The title of the project is PCMH MAT. Goals and objectives are: 1. Through the delivery of MAT and integrated COD treatment, improve the capacity of persons with SMI and OUD to achieve sustained recovery from COD and to reduce health risks associated with opioid abuse. Objectives include: 80% of clients enrolled in MAT will remain in MAT and COD treatment services for a minimum of 6 months; 100% of clients enrolled in MAT will complete Crisis Plans within 4 weeks of enrollment and 60% of MAT clients will complete Relapse Prevention Plans within 6 months of project enrollment; 60% of MAT clients will demonstrate clinically significant improvements in psychosocial functioning and life satisfaction after 6 months of enrollment. 2. Through Care Coordination and Peer Outreach to support persons with SMI in MAT, improve client engagement in community-based health care and recovery support networks. Objectives include: 80% of MAT clients will participate in a minimum of 3 contacts with Peer Outreach workers within 3 months of enrollment; 50% of MAT clients will engage in a minimum of 6 community based support activities within 12 months of enrollment; 50% of MAT clients will demonstrate improvements in clinical measures of chronic health conditions associated with polysubstance abuse. The PCMH MAT Project will serve 80 unduplicated clients in Year 1 of the project, 100 additional unduplicated clients in Year 2 and 100 additional unduplicated clients in Year 3. a total of 280 unduplicated clients will be served over the 3 years of the Project. The Project Evaluator has completed over 30 evaluations on SAMHSA projects since 2005.