Background: Postpartum depression is an important and common disease that may be exacerbated and prolonged if not diagnosed or treated early. It may affected by various factors including moral intelligence and social adjustment. The aim of this study was to investigate the relationship between moral intelligence, social adjustment, and postpartum depression in women referring to Birjand health centers. Materials and methods: In this descriptive-correlational study, the statistical population included all mothers who referred to health centers during the first six to eight weeks after delivery. Among the psychological centers, five centers were randomly selected and then 200 subjects with available sample were participated in the study. The research instruments were Edinburgh's standard postpartum depression questionnaire, moral intelligence questionnaire, and Wiseman's Social Adjustment Scale (1974). Data were analyzed using Pearson correlation coefficient test and regression analysis. Results: There was a significant relationship between moral intelligence, social adjustment and depression (p<0. 05). Conclusion: Considering the effect of mothers’ postpartum depression on their moral intelligence and adjustment, the accuracy and attention of health groups in postpartum referrals based on timely diagnosis of depression is necessary.