Objective: To examine neurophysiological correlates of attentional processing in children with oppositional-defiant disorder (ODD) independent of ADHD symptoms. Method: Thirteen children with oppositional-defiant disorder without comorbid ADHD symptoms and 13 healthy control children (all 11 years) performed a cued Continuous Performance Test (CPT-AX). Event-related potentials (ERP) to cue and target stimuli were examined for group differences. Results: Children with ODD showed significantly reduced parietal P3a and P3b amplitudes to cues and to targets, compared with healthy controls. ERP amplitudes correlated with oppositional and aggressive behavior scores. Conclusions: Event-related potentials revealed reduced orienting to cues and reduced executive target processing in children with ODD. These findings indicate that ODD children show neurophysiological deviances independent of ADHD comorbidity.