This study examines program elements related to reductions in drug use and crime among Drug Treatment Courts (DTC) participants as well as theoretical mechanisms--increased social controls and improved perceptions of procedural justice--expected to mediate the effects of DTC on these outcomes. Data are from 157 research participants interviewed three years following randomization into treatment and control conditions in the evaluation of the Baltimore City DTC. Findings indicate that perceptions of procedural justice reduce crime and that social controls reduce drug use. Hearings attended, drug testing, and drug treatment reduce drug use. Participation in the DTC increases the number of judicial hearings attended, which directly reduces drug use and indirectly reduces crime by increasing perceptions of procedural justice. Participation in the DTC increases social controls both directly and indirectly by increasing the duration of drug treatment. These increased perceptions of social control reduce drug use. Implications for DTC's are discussed. (Contains 6 tables, 1 figure, and 6 notes.)