BACKGROUND: Though prenatal organophosphate pesticide (OP) exposure has been associated with lower intellectual quotient and behavioral disorders in childhood, factors related to later delinquency, no research has directly evaluated the impact of OPs on delinquency. OBJECTIVE: To evaluate the association between prenatal and childhood OP exposure and juvenile delinquency in Mexican-American youth in the Center for Health Assessment of Mothers and Children of Salinas (CHAMACOS). METHODS: We measured dialkyl phosphate (DAPs) urinary metabolites of OPs in two prenatal maternal samples and in five child samples collected between six months and five years of age. Youth completed delinquency questionnaires at 16 years. We examined associations of prenatal and childhood DAPs with several delinquency outcomes (n=313) using survival and generalized linear models. RESULTS: Almost 60% of youth reported delinquent acts (mostly minor), and 8% reported a police arrest. We observed largely null results of prenatal or childhood DAP concentrations and delinquency outcomes, with some isolated associations. A ten-fold increase in maternal dimethylphosphate (DM) concentrations measured after 20 weeks gestation was associated with an earlier age of first delinquent act (Hazard Ratio=1.38, 95% CI: 1.01, 1.88) and an increased Odds Ratio (OR) of having committed 1-3 or ?4 delinquent acts, compared to the no delinquency reference group (OR=1.77, 95% CI: 1.01-3.08 and 2.17, 95% CI: 1.13-4.17, respectively). Higher childhood diethylphosphate (DE) concentrations were associated with a later age of first delinquent act (HR: 0.67; 95% CI: 0.46-0.97). DISCUSSION: We did not find strong evidence of association between prenatal or childhood OP exposure and juvenile delinquency in the present cohort. There is an increasing literature that relates OP exposure to neurobehavioral impairments in childhood, and there is a need to understand long-term potential neurodevelopmental effects of early-life OP exposure.