Background: Veterans with schizophrenia and other serious mental illnesses (SMI) are at elevated risk for co-occurring chronic medical conditions resulting in increased risk of disability high health care spending, reduced quality of life and early mortality. Physical wellness is increasingly recognized as a key component of the VA's commitment to developing recovery-oriented and veteran-centered mental health treatment. There is also growing recognition of the value of interventions that promote and improve patient self-management of chronic medical conditions. Building on the established efficacy of consumer facilitated medical illness self- management programming used in the general population and two recent adaptations for use with SMI adults in the public health sector (including our own evaluation of an intervention called Living Well), we propose to complete a randomized controlled effectiveness trial of our Living Well intervention and simultaneously conduct a well specified process evaluation to optimize knowledge accrual regarding important factors that may improve future adoption, implementation and sustainability of the Living Well intervention in the VA system of care. Aims: Primary AIM 1: Complete a randomized controlled effectiveness trial of our Living Well intervention with 250 veterans with SMI and at least one co-occurring chronic medical condition and evaluate the intervention's effects on functional and service related outcomes. We hypothesize that those randomized to the Living Well intervention will, in comparison to those randomized to a medical illness education and support group, demonstrate improved general health functioning including physical and emotional functioning as well as reduced rates of medical emergency room visits. We will also evaluate intervention effects on more proximal attitudinal and behavioral outcomes and assess how these factors mediate improvement in the functional and services related outcomes. Primary AIM 2: Complete a well specified process evaluation based on the RE-AIM evaluation framework to better understand contextual factors that can improve the Reach, Effectiveness, Adoption, Implementation and Maintenance which together determine the potential public health impact of the Living Well intervention. Methods: A mix of temporally overlapping quantitative and qualitative methods will be used to maximize integration and synthesis of data streams across the two aims to optimize knowledge accrual. Impact: Despite the growing recognition that self-management strategies hold enormous promise for improving quality and outcomes of care for chronic medical illnesses, and the fact that self-management is gaining prominence as a mental health recovery oriented treatment focus, there are currently no evidence-based peer facilitated medical illness self-management interventions available for dissemination within the VA mental health system. Our proposed study is designed to both generate evidence supporting the effectiveness of a peer co-facilitated intervention and to help speed throughput to public health impact by collecting important contextual information about factors that may improve future dissemination and implementation efforts.