The cost findings in this study indicate that Oregon's adult drug courts are both beneficial to participants and beneficial to Oregon taxpayers. Taking into account the investment of $18,696 per person, for just those participants included in this study, the net savings to Oregon after 5 years was $56,550,000, nearly $57 million. Given the significant taxpayer savings demonstrated in this study, the best use of State funds for offenders with drug possession and other drug-related charges is to put funds in drug court programs that will reduce the need for jail and prison cells. Among the many best practices identified are the inclusion of law enforcement officials on the drug court team; the provision of health and dental care; the development of written rules or guidelines regarding the team's response to participant behavior; requiring participants to attend drug court sessions once every 2 weeks; the use of evaluation feedback to make program modifications; and training for new court judges that is provided by prior drug court judges. The study collected information on program costs and recidivism-related costs, with "recidivism" defined as any new arrest (not conviction) that occurs after the date of drug court entry. 20 tables, 33 references, and appended listing of Oregon adult drug courts that participated in the research