Diagnosis of borderline personality disorder (BPD) during episodes of major depression (MDE), although clinically important, is complicated in several respects when using self-report methods. Structured interview data were used to select a group of patients with comorbid BPD (n=21) from a sample of outpatients presenting with MDE. This group was compared with a group of MDE patients without BPD (n=24) and with a group of community controls (n=20) using self-report data from the Personality Assessment Inventory (PAI), the revised Personality Diagnostic Questionnaire (PDQ), and the Beck Depression Inventory (BDI). Analyses revealed that the BPD group obtained significantly higher scores on PAI and PDQ scales measuring features of BPD and on the PAI Negative Impression Management scale. The severity and type of MDE symptoms reported on the PAI and BDI did not differentiate the clinical groups. These data show that useful information for the diagnosis of BPD during depressive episodes can be gathered from self-report assessment instruments like the PAI.