Studies on postpartum depression (PPD) in Iran have focused on prevalence and risk factors. There is little information available on the ethnic risk factors of PPD. We aimed to evaluate prevalence and some ethnic risk factors of PPD among women in West Azerbaijan, Mahabad, Iran. Twelve hundred mothers (600 Kurdish women, 600 Azeri women) who visited Mahabd public health centres for immunisation of their eight week old infants were interviewed about symptoms of depression. Most of the participants (89%) completed the questionnaire independently, while 11% required assistance by midwives because they were illiterate. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess depression. In the study, 36.3% of women had high depression scores (i.e. a score ≥13 indicated a higher risk of PPD). The mean depression score among Kurdish women was 14.77, and Azeri women 12.99. The common risk factors for higher scores were: younger mothers, unplanned pregnancy, poor economic status, mothers who did not work outside the home, having an infant with health problems, and poor paediatric care. Women from different ethnic backgrounds appeared to have different levels of emotional wellbeing, with Kurdish women experiencing higher levels of depressive symptoms. It appears that timing, as well as the quality of postpartum care, should be reexamined to address individual ethnic needs.