Relatively little is known about the efficacy of the therapeutic community as an intervention for drug abusers. The few published outcome studies vary widely in their conclusions; some claim extraordinary success while others cite much more modest results. This study reports the incidence of behavior changes (drug use, criminality, and unemployment) among 208 addicts, most of whom were White middle-class heroin users, both graduates and“splitees,”who participated in one of two California therapeutic communities. One program lasted 3 months and the other 10-12 months. Follow-up interviews conducted 11-18 months after participants left the treatment setting found only nine individuals, 4.3% of the participants, who totally abstained from drugs. There was, however, a marked decrease from preintervention incidence of drug use, crime, and unemployment. The most impressive behavior changes occurred among those who participated in the long-term program, as contrasted with the shorter one, and among those who graduated, as compared with those who withdrew before program completion.