The study involved a 200-man housing unit at a medium-security correctional facility in San Diego. The TC program actively recruited volunteers from the general prison population by making presentations to inmate groups and posting recruitment information. The original sample included 715 subjects who were followed up at 12 months post-release from prison. Of 493 subjects who had been on parole 3 or more years, 15 were deceased. Return-to-custody data were examined for the remaining 478 subjects who were at risk for at least 36 months. Baseline data were collected in face-to-face interviews with inmates who volunteered for the treatment program. Return-to-prison data were abstracted from the California Department of Correction's computerized Offender Based Information System. Outcomes for the 478 subjects at 36 months replicated findings of an earlier report on 12-month and 24-month outcomes, showing the best outcomes for those who completed both in-prison and aftercare TC programs. At 36 months, 27 percent of prison TC plus aftercare completers recidivated, versus 75 percent for other groups. In addition, a significant positive relationship was found between the amount of time spent in treatment and the time until return for parolees who recidivated. Reduced recidivism rates, however, for in-prison treatment found only at 12 and 24 months were not maintained at 36 months. Implications of the findings for research and policy are discussed. 29 references and 4 tables