Supportive housing is subsidized housing with on-site or closely linked services for chronically homeless persons. Most literature describing the effects of supportive housing on health service utilization does not describe use across multiple domains of services. We conducted a retrospective cohort study of 249 applicants to a supportive housing program; 114 (45.7%) were housed in the program. We describe the pattern of service use across multiple domains (housing, physical health care, mental health care, substance abuse treatment). We examine whether enrollment in supportive housing was associated with decreased use of acute health services (emergency department (ED) and inpatient medical hospitalizations) and increased use of ambulatory services (ambulatory medical and generalist care, mental health, and substance abuse treatment) as compared to those eligible but not enrolled. Participants in both groups exhibited high rates of service utilization. We did not find a difference in change in utilization patterns between the two groups [those that received housing (intervention) and those that applied, were eligible, but did not establish residency (usual care group)] comparing the two years prior to the intervention to the two years after. The finding of high rates of maintenance of housing is, in itself, noteworthy. The consistently high use of services across multiple domains and across multiple years speaks to the level of infirmity of this population and the costs of caring for its members. (Authors)