Data were obtained from a study of youthful offenders with chemical dependency treatment needs who were incarcerated at the TYC. Two groups were compared: a treatment group that received substance abuse counseling and services through the CDTP and a control group with chemical dependency needs who did not receive treatment. The CDTP features were a caseworker-to-student ratio of 1:8 to 1:10; individualized focus on each student's history and needs; optimal exposure to treatment (8 months); attention to the relationship between drug abuse and criminal behavior; group counseling and peer accountability; education curriculum that is experiential and geared to learning abilities of students; emphasis on relapse prevention and community reintegration; and the development of cognitive skills. Findings show that youths in treatment did not perform better upon release as measured by drug, violent, and property rearrest rates as well as placement in higher custody levels. This was true whether the evaluation examined released and paroled youths or paroled youths only. There was some variation in the factors that predicted recidivism, but there were few statistically significant interactions between the treatment/control group variables and other variables, indicating that generally the same factors that predicted recidivism among the treatment group also were similarly predictive of recidivism among the control group. The most important exception to the above findings was the presence of statistically and substantively significant interactive effects between treatment and treatment sites. Treatment differed in its impact on recidivism, depending on where treatment was provided. Overall, the evaluation findings suggest that treatment can impact drug use and offending, but only if program implementation is carefully monitored across multiple sites in State youth correctional agencies. 43 references, 5 tables, and appended program exit assessment