The 12-month cost-effectiveness of juvenile drug court and evidence-based treatments within court were compared with traditional Family Court for 128 substance-abusing/dependent juvenile offenders participating in a 4-condition randomized trial. Intervention conditions included Family Court with community services (FC), Drug Court with community services (DC), Drug Court with Multisystemic Therapy (DC/MST), and Drug Court with MST enhanced with a contingency management program (DC/MST/CM). Average cost-effectiveness ratios for substance use and criminal behavior outcomes revealed that economic efficiency in achieving outcomes generally improved from FC to DC, with the addition of evidence-based treatments improving efficiency in obtaining substance use outcomes. (Contains 2 tables.)