Nearly two-thirds of homeless adults suffer from mental illness and/or substance abuse. Supportive housing programs offer a combination of affordable and supportive services to address these problems and enhance residential stability. Moving homeless and hard-to-house individuals into supportive housing should reduce demand for shelter services and may have a beneficial effect on health status and patterns of utilization. This project used a quasi-experimental design to (1) compare individuals entering the Evangel Hall supportive housing program and wait-list individuals to determine changes in housing status, health status, alcohol and drug use, legal involvement, quality of life, and use of inpatient, emergency and outpatient health care services; and (2) to determine the cost-effectiveness of the program compared to usual care (wait-list individuals); and (3) to develop a study design that is suitable for application to other supportive housing programs, for diffusion to other cities as the opportunity arises.