Introduction: Integrated mental and physical health care has the potential to improve health outcomes. A behavioral health organization established a reverse integration program site using a co-located model to provide primary care services to patients receiving behavioral health services. We ask whether this model of co-located care was effective in improving a range of physical health outcomes for clients. This program was funded with a grant from the Substance Abuse and Mental Health Services Administration Primary and Behavioral Health Care Integration. Method: Patients received services in a community mental health setting that embedded primary care services. The population included adult patients with mental illness, substance use disorder (SUD), or cooccurring medical diagnoses in an urban setting. Just under half of the patients identified as non-White, and over one quarter identified as Hispanic. These characteristics demonstrate a medically complex and underserved population. This description and exploratory analysis utilized National Outcome Measures data and clinical health measures from electronic health records. We stratified data by SUD and mental illness diagnoses. We measured changes in health outcomes for this complex population of 532 patients from 2015 to 2019. Results: From enrollment to last visit, patient outcomes improved for blood pressure and cholesterol. Conversely, waist circumference and breath carbon monoxide levels significantly worsened. Discussion: This reverse integration co-location program demonstrates that positive health outcomes can be achieved through evidence-based care, adaptable clinic arrangements, and robust community connections and support. More work is needed to generate positive health outcomes in medically complex patients.Meghan K. Chambers https://orcid.org/0000-0001-7932-4427 Maximilian J. Brimmer https://orcid.org/0000-0002-4460-4899 Kim Griswold https://orcid.org/0000-0002-0321-8879We gratefully acknowledge the assistance of Dr.