We used multiaxial structured interviews and questionnaires to evaluate the ability of self-reports on seven personality dimensions to predict independent interview diagnoses of DSM-III-R personality disorders. We studied 136 consecutive adult psychiatric inpatients, excluding those with psychosis, organic mental disorders, and severe agitation. Sixty-six patients had interview diagnoses of DSM-III-R personality disorders. Most also had mood disorders. We confirmed the hypotheses that self-reports of low self-directedness and cooperativeness strongly predicted the number of personality symptoms in all interview categories, whereas the other factors distinguished among subtypes as predicted. Self-directedness and cooperativeness also predicted the presence of any personality disorder by differentiating patients varying in risk from 11% to 94%. Patients in clusters A, B, and C were differentiated by low reward dependence, high novelty seeking, and high harm avoidance, respectively. We conclude that low self-directedness and cooperativeness are core features of all personality disorders and are validly measured by the seven-factor Temperament and Character Inventory, but not the five-factor Neuroticism-Extraversion-Openness inventory. Each DSM-III-R personality disorder category is associated with a unique profile of scores in the seven-factor model, providing an efficient guide to differential diagnosis and treatment.