OBJECTIVE: This study sought to document the prevalence of dissociative experiences in adult female inpatients with borderline personality disorder and to explore the relationship between dissociation, self- mutilation, and childhood abuse history. METHOD: A treatment history interview, the Dissociative Experiences Scale, the Sexual Experiences Questionnaire, and the Hamilton Depression Rating Scale were administered to 60 consecutively admitted female inpatients with borderline personality disorder as diagnosed by the Structured Clinical Interview for DSM-III-R Personality Disorders. RESULTS: Fifty percent of the subjects had a score of 15 or more on the Dissociative Experiences Scale, indicating pathological levels of dissociation. Fifty-two percent reported a history of self-mutilation, and 60% reported a history of childhood physical and/or sexual abuse. The subjects who dissociated were more likely than those who did not to self-mutilate and to report childhood abuse. They also had higher levels of current depressive symptoms and psychiatric treatment. Multiple regression analysis demonstrated that each of these variables predicted dissociation when each of the others was controlled for, and that self-mutilation was the most powerful predictor of dissociation. CONCLUSIONS: Female inpatients with borderline personality disorder who dissociate may represent a sizable subgroup of patients with the disorder who are at especially high risk for self-mutilation, childhood abuse, depression, and utilization of psychiatric treatment. The strong correlation between dissociation and self-mutilation independent of childhood abuse history should alert clinicians to address these symptoms first while exercising caution in attributing them to a history of abuse.