OBJECTIVE: This study was conducted to determine whether trauma variables and certain behavioral correlates are differentially prevalent in borderline personality disorder patients with greater and those with lesser dissociative experience. METHOD: Subjects were 62 female inpatients, all meeting DSM-III-R criteria for borderline personality disorder, 14 of whom also had a concomitant dissociative disorder diagnosis. Structured interviews and published scales were used to collect data addressing a priori hypotheses. RESULTS: Univariate analyses supported hypotheses that patients with borderline personality disorder and greater dissociative experience are characterized by more self-reported traumatic experiences, posttraumatic symptoms, behavioral dyscontrol, self-injurious behavior, and alcohol abuse. Multivariate analyses suggested that scores on the Dissociative Experiences Scale were predicted particularly by adult sexual assault, behavioral dyscontrol, and both sexual and physical abuse in childhood. CONCLUSIONS: These results support the use of the Dissociative Experience Scale as a brief screening instrument to aid in the identification of borderline personality disorder patients with prominent posttraumatic and dissociative disorders. Patients with borderline personality disorder seem to be characterized by somewhat different life experiences, treatment histories, and behavioral presentations depending on their level of dissociative experience, even though they meet the same DSM-III-R criteria. Neither extreme view of the overlap in diagnostic populations was supported.