Objective: Personality traits have impacts on individuals' response to stress and mood expression. The current study aimed to investigate the profile of personality traits in patients with bipolar disorders and major depressive disorder (MDD). Familial aggregation of personality traits in mood disorder families was also evaluated. Methods: We recruited 260 clinical patients of MDD (92), bipolar disorder-I and II (BP-I = 111, BP-II = 57), 190 first-degree relatives, and 180 controls. Four personality traits were assessed using the Eysenck and Tridimensional Personality Questionnaires, including Extraversion (E), Neuroticism (N), Harm Avoidance (HA), and Novelty Seeking (NS). The magnitude of familiality of personality traits in mood disorder families was evaluated by mixed models and intra-class correlation coefficients (ICC). Results: Patients with mood disorders had lower E. and higher N, HA and NS than controls. Unaffected relatives were not differed from controls in the four personality traits. BP-I had higher E, NS and lower N. HA than MDD patients (p