Data from neuropsychological tests indicate that brain dysfunction is a correlate of a form of persistent antisocial behavior that afflicts about 5 percent of males. Neuropsychological tests predicted variance in delinquent behavior independently of appropriate control variables. However, neuropsychological test scores are not impressive univariate predictors of general delinquency. Instead, neuropsychological factors probably work in the context of interactions between person and context over the course of development, and they probably apply only to a small subgroup of offenders. The data indicate that urban poverty contributes both to neuropsychological deficits and to their exaggerated impact on subsequent development. However, further research is needed to clarify the data underlying the growing consensus that family and neighborhood adversity mediate the relationships between neuropsychology and antisocial outcomes. Finally, recent data from the Pittsburgh Youth Study suggest that efforts to improve children's neurological health should be an important part of crime prevention programs designed to improve inner-city conditions. Approximately 250 references