The programs operated in Pima County and Maricopa County and sought to reduce pretrial misconduct by systematic urine testing of defendants, including periodic monitoring of releasees through drug testing and sanctions for noncompliance. In each site, two phases of research were conducted. In the first phase, a sample of defendants was tested for drug use and followed in the community. The second phase involved experiments in which some defendants were assigned randomly to either ordinary release conditions or periodic drug testing with sanctions for noncompliance. Results of both phases of the research indicated that monitoring does not substantially affect pretrial misconduct. Findings indicated that programs of this type should anticipate only small effects, if any, on pretrial misconduct; that other methods probably work as well as drug tests; that sanctioning systems for drug test failures during the pretrial period are difficult to implement; and that pretrial drug screening is costly. Tables, figures, 5 references, and appended coding information