Background majority of neonate and maternal death is occurring in the first week of delivery. Therefore, utilization of postnatal care within the first week of delivery is essential to increase the survival of both a mother and newborn. Therefore, this study was aimed to assess the use of postnatal care in the first week of delivery and factors associated among women who gave birth in the last six weeks. Method A community-based cross-sectional study was conducted in the Dano District, one of the remotest districts in the Oromia Region of Ethiopia. A total of 274 women who gave birth during the last six weeks and selected using random sampling method were included in the study. Multivariate logistic regression was used to identify factors associated with the utilization of postnatal care within the first week of delivery. Finding with a p-value less than 0.05 is considered a statistically significant association. Result early postnatal care utilization is found to be (within the first week of delivery) was 23.7 percent. Mother given appointment after delivery [AOR=4.84, 95% CI= (1.46, 16.1)], have used postnatal care previous [AOR= 7.4, 95% CI= (2.9, 18.5)] and aware of postnatal care within first week of delivery [AOR=4.27, 95% CI= (1.46, 12.49)] were more likely to use the postnatal care within first week. The qualitative finding indicated traditional beliefs during postpartum also found to affect the use of postnatal care. Conclusion The utilization of postnatal care within first week of delivery in was low in the district. Therefore, creating awareness on the benefits of early postnatal care, and designing of strategies to decrease the effect of traditional belief on postnatal care recommended to improve the coverage.