The issue of delinquency among truant youths is insufficiently documented in the literature. There is a need to elucidate this issue, and assess the efficacy of interventions to reduce this problem behavior. The present National Institute on Drug Abuse (NIDA)-funded study addressed this gap by examining the impact of a Brief Intervention (BI), originally designed to address youth substance use, on their delinquent behavior over an 18-month follow-up period (for self-reported delinquency) and a 24-month follow-up period (for official record delinquency). A number of significant BI intervention effects with sizable effect sizes were found, as well as a number of marginally significant BI effects. In particular, significant reductions in arrest charges at 24-month follow-up for youths receiving BI services compared to controls were among the key findings of this study. Service delivery implications and directions for future analyses are discussed.