Children with persistent antisocial and aggressive behavior are diagnosed as having disruptive behavior disorder. The authors review evidence that antisocial children, and especially those who persist with this behavior as they grow older, have a range of neurobiological characteristics. It is argued that serotonergic functioning and stress-regulating mechanisms are important in explaining individual differences in antisocial behavior. Moreover, low fear of punishment and physiological underactivity may predispose antisocial individuals to seek out stimulation or take risks and may help to explain poor conditioning and socialization. The authors propose a theoretical model highlighting the interplay between neurobiological deficits and cognitive and emotional functioning as mediators of the link between early adversity and antisocial behavior problems in childhood. Implications for intervention programs are discussed.