The juvenile justice system relies heavily on residential treatment services for adolescents. Because treatment dropout limits the likely effectiveness of these services, in this study we examine the client and program characteristics associated with program retention among a sample of adolescent probationers referred to residential rehabilitation by the Juvenile Court in Los Angeles. Participants in the present study (n = 291) are a subset of those in the Adolescent Outcomes Project, conducted within RAND's Drug Policy Research Center, to examine the outcomes of youths entering treatment at seven residential treatment programs. Three months after a preadmission interview, youths were asked about their perceptions of counselors at the program, other residents, and their feelings of safety in the program. In addition, they were asked whether they needed and had received various services (e.g., job training, legal advice, family counseling). Results of a multivariate survival analysis revealed that pretreatment characteristics including motivation and substance use severity, as well as treatment program factors including safety, and perceived over- and underprovision of services, contribute significantly to the prediction of retention. Pretreatment environmental risk factors and ratings of program counselor and resident support were marginally significant. These results imply that changes in adolescent residential program delivery may serve to increase retention rates, thus improving long-term outcomes.