This study investigated the personality disorders of 21 recent-onset Bipolar Disorder patients using the revised Million Clinical Multiaxial Inventory (MCMI-II; Millon, 1987). Personality disorder assessments, conducted after patients' clinical symptoms had settled, indicated that 17 patients received at least one MCMI-II personality disorder diagnosis with a trend toward multiple diagnoses. Narcissistic, Antisocial, and Histrionic personality disorders were diagnosed most frequently and were the scales most elevated. Schizoid and Compulsive personality disorders were the scales least elevated. Diagnostic concordance between the MCMI-II and the Structured Interview for DSM-III Personality (SIDP; Pfohl, Stangl, & Zimmerman, 1983) was poor; the MCMI-II made more multiple diagnoses. Implications of the discrepancies between these instruments and suggestions for future research are discussed.