The Drug Court selected a target group, felony 3 drug possession defendants with no prior convictions, and established a three-phase diversion and treatment program to treat defendants on an outpatient basis. As the approach as evolved, other kinds of defendants have been included and treatment practices have been revised to include more locations as well as residential treatment for certain defendants. More than 3,000 defendants had entered the program as of the spring of 1993. Based on one version of measuring treatment program success, approximately 60 percent of the defendants could be classified as having favorable outcomes. With respect to criminal case processing, the Drug Court defendants had more diversion outcomes, longer case completion times, and fewer sentences of incarceration of more than 1 year than did other felony drug and nondrug outcomes. Drug court defendants also generated somewhat lower rates of rearrests as well as longer times until rearrest than did the comparison-group defendants. The analysis also revealed 18 implementation issues, including the importance of strong system support and an active judicial role. Figures, footnotes, appended tables and methodological information, and 17 references