Past research suggests that Type As are more aggressive than Type Bs. However, little is known about the nature of that aggression. The present two studies investigated the theoretical distinction between hostile aggression and instrumental aggression and examined the practical implications of this distinction. Study 1 used a modified version of the Buss teacher-learner procedure that allowed the isolation of hostile from instrumental acts. Results indicated that a prior task frustration produced greater aggression by Type As than Type Bs but only under conditions where the aggressive act could not affect a confederate's immediate performance (i.e., hostile aggression). Study 2 examined the representation of Type As and Type Bs among perpetrators of intrafamily violence. Results indicated that Type As were more likely than Type Bs to exhibit the extreme hostility found in child abuse. Both studies suggest that a lack of control may underlie the greater aggression displayed by Type As than Type Bs.