The authors evaluated personality dysfunction in 23 patients with primary obsessive-compulsive disorder and an age- and sex-matched group of patients with major depressive disorder. There were no significant differences between the two patient groups with respect to mean personality trait scores or the frequency or type of personality disorder diagnosis. A mixed personality disorder with avoidant, dependent, and passive-aggressive features was most commonly observed in the obsessive-compulsive group. There was a very low frequency of schizoid or compulsive personality disorder.