Juvenile drug court (JDC) programs have expanded rapidly over the past 20 years and are an increasingly popular option for rehabilitating juvenile offenders with substance use problems. Given the high cost of crime to society, an important economic question is whether and to what extent JDC programs reduce criminal activity among juvenile offenders. To address this question, the present study added an economic cost analysis to an ongoing randomized trial of JDC conducted in Charleston, South Carolina. Four treatment conditions were included in the parent study: Family Court with usual community-based treatment (FC, the comparison group), Drug Court with usual community-based treatment (DC), DC with Multisystemic Therapy (DC/MST), and DC/MST enhanced with Contingency Management (DC/MST/CM). The economic study estimated the cost of criminal activity for nine specific crimes at baseline (pretreatment) and 4 and 12 months thereafter. A number of methodological challenges were encountered, suggesting that it may be more difficult to economically quantify frequency and type of criminal activity for adolescents than for adults. The present paper addresses methodological approaches and challenges, and proposes guidelines for future economic evaluations of adolescent substance abuse and crime prevention programs.