Therapeutic communities have become increasingly popular among correctional agencies with drug-involved offenders. This quasi-experimental study followed a group of inmates who participated in a prison-based therapeutic community in a California state prison, with a comparison group of matched offenders, for more than 5 years after their initial prison release. Contrary to successes reported elsewhere, this study found no difference in new arrests and returns to prison between therapeutic community participants and the comparison participants after 5 years. Overall, more than 60% of both groups were returned to prison within 2 years following their initial release. After 5 years, the return-to-prison rate reached about 73% for both groups. The average time spent in prison following initial release was about the same for both groups. Rearrest offenses were also similar in both groups. Policy implications are discussed. (Contains 5 tables and 4 notes.)