The Bureau of Justice Assistance sponsored experimental evaluations of drug testing at the pretrial release stage in Milwaukee, Wisconsin, and Prince George's County, Maryland. The main objective was to test the assumption that intensive monitoring of drug use during pretrial release would reduce pretrial flight and crime levels. A system of graduated sanctions was devised for implementing drug testing programs at each site, in order to enforce defendant compliance with the drug monitoring program. Evaluation results showed that few defendants at either site had outstanding performance records. Only 2 percent in Prince George's County and 9 percent in Milwaukee recorded either a no-show or a positive test result. About 65 percent of Prince George's County and 56 percent of Milwaukee defendants recorded more than five violations of program requirements. Participation in the drug monitoring program did not decrease the rate of pretrial misconduct among drug offenders, and data indicated a substantial level of defendant noncompliance with program conditions. 16 references, 13 notes, 9 tables, and 2 figures