BACKGROUND: Identification of patients with a bipolar disorder (BPD) among those presenting a major depressive episode is often difficult, resulting in common misdiagnosis and mistreatment. Our aim was to identify clinical variables unrelated to current depressive episode and relevant to suicidal behavior that may help to improve the detection of BPD in suicide attempters presenting with recurrent major depressive disorder. METHOD: 211 patients suffering from recurrent major depressive disorder or BPD, hospitalized after a suicide attempt (SA), were interviewed by semi-structured interview and validated questionnaires about DSM-IV axis I disorders, SA characteristics and a wide range of personality traits relevant to suicidal vulnerability. Multivariate logistic regression analysis was performed to determine differences between RMDD and BPD attempters. RESULTS: Logistic regression analysis showed that serious SA and family history of suicide are closely associated with a diagnosis of BPD [respectively OR=2.28, p=0.0195; OR=2.98, p=0.0081]. The presence of both characteristics increase the association with BDP [OR=4.78, p=0.005]. Conversely, when looking for the features associated with a serious SA, BPD was the only associated diagnosis [OR=2.03, p=0.004]. Lastly, affect intensity was higher in BPD samples [OR=2.08, p=0.041]. LIMITATIONS: Retrospective nature of the study, lack of the separate analysis of bipolar subtypes. CONCLUSION: Serious suicide attempt and a familial history of completed suicide in patients with major depression seem to be a clinical marker of bipolarity. Facing suicide attempters with recurrent depression, clinician should be awareness to these characteristics to detect BPD.