Housing First programs offer chronically homeless individuals immediate housing as a foundation for the delivery of a range of other supportive services, such as mental health and/or substance use disorder services and social service supports. This report summarizes a study examining the effect of the Housing First model on health care utilization and costs among chronically homeless individuals enrolled in MassHealth. The findings from this study demonstrate the effectiveness of a permanent housing and supportive services program in reducing total health care utilization and costs among chronically homeless individuals.