Inpatient suicide attempters (n = 37) were compared with never-suicidal psychiatric controls (n = 29) with respect to prevalence and severity of personality disorder, history of aggression and assaultive behavior, and other measures of impulsive violence. Attempters, compared with controls, were more likely to show evidence of personality disorder or trait, particularly those of the borderline type. Attempters showed greater number of borderline symptoms than did controls, even after removing the item relating to suicidality. There were no differences between the groups with respect to lifetime history of aggression, history of assaultive behavior, or self-report measures of a tendency to impulsive aggression. Those attempters with personality disorder were much more likely to have made a previous attempt. The apparently high prevalence of personality disorder among adolescent inpatient suicide attempters indicates that the social impairment associated with personality disorder be viewed as an important aspect of treatment.