BackgroundPostpartum depression is a non-psychotic disorder that happens during the first 1year after childbirth. It affects both the mother’s health and child’s development and is given significant public health concern in developed countries. However, in developing countries including Ethiopia, postnatal care is mainly concerned with obstetric problems and the baby’s health, while the psychological well-being of the mother is given little attention. Therefore, this study was aimed to assess the magnitude and associated factors of postpartum depression among women in Nekemte town, East Wollega zone, West Ethiopia, 2019.MethodsCommunity-based cross-sectional study was conducted on 295 postnatal women, from May 15 to June 5, 2019, in Nekemte town. The study participants were selected by a simple random sampling method and interviewed using structured questionnaires. Multivariable logistic regression was used to find the independent variables which are associated with postnatal depression. All associations between dependent and independent variables and statistical significance were measured using odds ratio at 95% confidence interval and p-value less than 0.05.ResultsFrom the total of 295 women sampled, 287 were participated in the study. Out of these 287 women participated, 20.9% had developed postnatal depression. Unplanned pregnancy (AOR = 7.84, 95% CI: 3.19, 19.26), Being first time mother (AOR = 4.99, 95% CI: 1.54, 16.09), History of previous depression (AOR = 3.06, 95% CI: 1.06, 8.82), Domestic violence (AOR = 5.92, 95% CI: 2.44, 14.40), History of substance use (AOR = 3.95, 95% CI: 1.52, 10.30) and poor social support (AOR = 6.59, 95% CI: 2.25, 19.29) were significantly associated with postnatal depression.ConclusionIn this study, the magnitude of postnatal depression was found moderate compared to other studies. Perinatal depression screening and intervention need to be integrated with maternal health care services, especially for mothers at risk of postnatal depression.