BACKGROUND:The purpose of this study was to explore the association of five factors personality traits, as predictor variables, with the anxiety and depression as joint dependent variables in an Iranian adult population. SUBJECTS AND METHODS:A total of 3175 subjects living in Isfahan participated in this cross-sectional population-based study (SEPAHAN) and completed self-administered questionnaires about demographic, life style, gastrointestinal disorders, personality traits, social support, and psychological problems. Data was analyzed using bivariate multiple binary logistic regression in R Free statistical software. RESULTS:The results indicated high scores of neuroticisms increase the risk of anxiety and depression after adjustment for the potential confounders in total sample (OR (95% CI): 1.22 (1.19-1.24) and 1.19 (1.17-1.21), respectively) as well as in both male and female. In contrast, joint inverse associations were found between anxiety and depression with high extraversion (OR (95% CI): 0.90 (0.88-0.92) and 0.91 (0.89-0.92), respectively), agreeableness (0.93 (0.91-0.96) and 0.94 (0.92-0.96) respectively) and conscientiousness scores (0.95 (0.93-0.97) and 0.95 (0.94-0.97) respectively) as well as in both male and female. Furthermore, higher scores of openness had significant inverse association with depression in male. CONCLUSION:The present study indicated that higher scores of neuroticism, however lower extraversion, conscientiousness and agreeableness scores are risk factors for both anxiety and depression in Iranian adult population. It is suggested to perform family studies or twin and genetic association studies with considering combinations of personality traits (personality styles), and also measuring personality traits at the facet level.