BACKGROUND Maternal health status might have an important effect on breastfeeding, growth, and general health of the infants. OBJECTIVES This study was conducted to assess the association between maternal mental health and breastfeeding status of mothers in Kashan province. PATIENTS AND METHODS This case-control study was conducted on 458 mothers in two groups of unsuccessful breastfeeding (case) and successful breastfeeding (control) attending Kashan province health clinics. In this study, the GHQ questionnaire and clinical interview were employed to collect data. The data were statistically analyzed using Chi-square and Fisher's exact tests. RESULTS It was found that mothers of the case group had a greater susceptibility to depression than those of the control group, that is, breastfeeding status was directly associated with susceptibility to depression (P = 0.001, OR = 5.48). Furthermore, there was a significant association between basic characteristics such as maternal occupational status (P = 0.04) or their educations (P = 0.006) with breastfeeding. Besides, clinical interview revealed that mixed depression and anxiety disorder was the most prevalent type of psychological disorder in the case group. CONCLUSIONS Screening depression during pregnancy and postpartum period appeared to be necessary and it should be incorporated into prenatal and postnatal care due to its influence on mothers' successful breastfeeding.