Abstract
In 1992, the California Department of Corrections established, under legislative authorization, the California Substance Abuse Treatment Facility (CSATF). With a treatment capacity of 1,478, the CSATF is currently the largest in-prison therapeutic community in the state, and one of the largest in the country. A number of measures from a process evaluation of the program suggest that the presence of a therapeutic community within a prison is associated with significant advantages for management of the institution-including lower rates of infractions, reduced absenteeism among correctional staff, and virtually no illicit drug use among inmates. These objective data are further supported by responses from inmates and correctional staff at the institution who participated in focus groups.