The occurrence of personality disorders was investigated in 36 patients with obsessive-compulsive disorder by means of the SCID Screen questionnaire. In addition, the personality dimensions were explored by means of the Temperament and Character Inventory (TCI). In total, 75% of the patients fulfilled the criteria for a personality disorder according to the SCID Screen questionnaire, mostly (55%) within cluster C. Several significant correlations were found between the separate personality disorders (PD) and subscales of the TCI, the most pronounced being between avoidant and obsessive-compulsive PD and novelty-seeking and self-directedness. Strong correlations were also found between self-directedness and paranoid and borderline PD. In multiple regressions where the presence of PD in clusters A, B and C, respectively, were used as dependent variables and where the separate subscales of the TCI were used as independent variables, the multiple R reached 0.68, 0.76 and 0.80 in clusters A, B and C, respectively. Thus 46–64% of the variance in the personality disorder clusters could be explained by the TCI subscales.