Prior findings on P3 event-related potential deficits in antisocial populations are mixed and it has been suggested that these abnormalities may not apply to psychopaths. A meta-analysis of 38 studies (total N=2616) was conducted to investigate the relationship of P3 measures to antisocial behavior. Reduced P3 amplitudes (d=0.252, p<.001) and longer P3 latencies (d=0.130, p=.019) were significantly associated with antisocial behavior across all electrode sites, and when using both normal and non-normal control groups. A significant moderating effect of electrode site indicated longer latencies at Fz but not Pz. Compared to non-psychopathic offenders, psychopathic offenders showed P3 amplitudes impairments in standard oddball tasks, but not other tasks. Findings suggest that reduced P3 amplitudes and prolonged P3 latencies may reflect inefficient deployment of neural resources in processing cognitive task-relevant information in individuals characterized with generic antisocial behavior (i.e., aggression, antisocial personality disorder, conduct disorder/oppositional-defiant disorder, and psychopathy), whereas this association in psychopaths may be moderated by the type of tasks.