Adult criteria for borderline personality disorder distinguished a group of 27 inpatient adolescent girls from 23 nonborderline inpatient female comparison subjects. The two groups were compared on retrospectively assessed variables measuring psychological, familial, and constitutional factors. Variables most likely to predict borderline personality disorder included history of disrupted attachments, maternal neglect, maternal rejection, grossly inappropriate parental behavior, number of mother and father surrogates, physical abuse, and sexual abuse. Families of borderline adolescents were chronically disrupted, particularly during the patients' early childhoods. The traumatic childhood experiences of the borderline adolescents were similar to those of adults with borderline personality disorder in recent studies.