This study addresses 5 unresolved issues in the neuropsychology of antisocial behavior using a community sample of 325 school boys in whom neurocognitive measures were assessed at age 16-17 years. Antisocial behavior measures collected from age 7-17 years were cluster analyzed and produced 4 groups: control, childhood-limited, adolescent-limited, and life-course persistent. Those on the lifecourse persistent path and also on the childhood-limited path were particularly impaired on spatial and memory functions. Impairments were independent of abuse, psychosocial adversity, head injury, and hyperactivity. Findings provide some support for the life-course persistent versus adolescent-limited theory of antisocial behavior and suggest that (a) neurocognitive impairments are profound and not artifactual and (b) childhood-limited antisocials may not be free of long-lasting functional impairment.