Background: The aim of the study was to find the prevalence of interpersonal rejection sensitivity (IRS) (a personality trait in DSM-IV) in bipolar II and unipolar depression. Methods: 557 consecutive unipolar and bipolar TT outpatients, presenting for depression treatment, were interviewed with the DSM-IV Structured Clinical Interview and the Global Assessment of Functioning Scale. DSM-IV atypical features criteria (which include IRS) were followed. Results: IRS was significantly more common in bipolar II than in unipolar patients (37.8% vs. 20.5%, odds ratio 2.3, P = 0.0000). Sensitivity and specificity for bipolar II diagnosis were 37.8% and 79.4%. Conclusions: IRS personality trait seems to be more common in bipolar II than in unipolar depression. Limitations: reliability of bipolar IT diagnosis, non-blind, cross-sectional assessment, single interviewer. (C) 2000 Elsevier Science B.V. All rights reserved.