This study attempted to identify a specific personality disorder (PD) cluster associated with poor outcome after a 4-month course of antidepressant therapy. Subjects were 96 consecutive outpatients with major depression. The Structured Clinical Interview for DSM-III-R (SCID) was used to make Axis I and Axis II diagnoses. To evaluate the net effect of each PD cluster on the outcome of depression, a log-linear model was applied. The analysis showed that the presence of a PD from cluster A was significantly correlated with the 4-month outcome of depression.