Previous research has articulated the conceptual differentiation of impulsive and premeditated aggression. Little, if any, of this research has examined personological differences among adolescents with aggression-oriented pathology, and little, if any, has examined both self and informant perspectives. The current study examined such differentiation within a Conduct Disorder population in which normal and pathological personality characteristics were examined via self- and informant-report. Results indicated the two forms of aggression were independent: high impulsive aggression was associated with high Neuroticism, but high premeditated aggression was associated with low Agreeableness and high Extraversion. Overall, adolescents high in impulsive aggression had a pattern of personality characteristics that are seen as socially-detached and emotionally volatile. In contrast, adolescents high in premeditated aggression had a pattern of characteristics seen as egocentric and socially-engaged but without concern for others. The results have implications for the social and motivational mechanisms producing the two forms of aggression.