20 euthymic bipolar teens were assessed using the Personality Disorders Examination. 35% met DSM-III-R criteria for at least 1 personality disorder. 3/20 had a bordlerline personality diagnosis. The bipolar illness with personality disorder group differed significantly from the bipolar illness without personality disorder group in terms of increased lithium unresponsiveness & neuroleptic treatment at time of assessment but not in terms of, among others, age, sex and number of suicide attempts.