Subjects with borderline personality disorder (N = 21) or borderline traits (N = 11) and nonborderline subjects with closely related diagnoses (N = 23) were interviewed in depth regarding experiences of major childhood trauma. Significantly more borderline subjects (81%) gave histories of such trauma, including physical abuse (71%), sexual abuse (68%), and witnessing serious domestic violence (62%); abuse histories were less common in those with borderline traits and least common in the subjects with no borderline diagnosis. These results demonstrate a strong association between a diagnosis of borderline personality disorder and a history of abuse in childhood.