This study examined whether comorbid personality disorders and other clinical factors were predictive of functional morbidity in bipolar I disorder. Fifty-one participants with a diagnosis of bipolar I were assessed for personality disorders and administered measures of symptomatic and functional outcomes approximately 1 year after a psychiatric hospitalization. Forty-five percent of the sample met criteria for at least one personality disorder, and patients with a personality disorder reported higher levels of residual symptoms at the time of assessment. Two thirds of participants displayed compromised functional outcomes. The three outcome domains examined (i.e., occupational, residential, social/leisure) were related to a range of clinical characteristics, and for all three, either the presence of a personality disorder diagnosis or maladaptive trait scores was associated with impaired functioning. These relationships, however, were not independent of mood symptoms according to multivariate analysis. Residual depression predicted poorer residential and social/leisure outcomes independent of personality disorders or maladaptive traits.