This article describes a TC-oriented aftercare program for homeless mentally ill chemical abusers (MICAs) in a supported housing facility, and presents some preliminary data on program effectiveness. The study divided the clients who had completed a residential modified TC program into two groups--those who participated in the TC-oriented supported housing program and those who did not. The data show similarities in the profile of the two groups. Improvement in negative behaviors (e.g., drug use and crime) occurred during the residential program and stabilized during the supported housing program, while improvement in prosocial behaviors (e.g., psychological functioning and employment) was incremental and continuous over the course of both programs. Those who participated in the TC-oriented supported housing program demonstrated significantly better outcomes than those who did not. These findings provide preliminary evidence for the effectiveness of a TC-oriented supported housing program as an aftercare strategy for homeless MICA clients following residential treatment.