Introduction:Infant mortality is one of the commonest health-related indicators used to assess the health status of the community. Children born in Sub-Saharan Africa are at highest risk of infancy death in the world. Ethiopia, in Sub-Saharan Africa, is a country with high infant mortality. Oromia region is among the regions with high infant mortality rate in Ethiopia. Therefore, this study aimed to identify determinants of infant mortality in Oromia region, Ethiopia.Methods:The source of data for this study was 2019 Ethiopian Mini Demographic and Health Survey. Multivariable logistic regression model was employed to identify the determinants the infant mortality. An adjusted odds ratio (OR) with a 95% CI was used examine the determinants of infant mortality.Results:A total of 719 live births born 5 years preceding the survey were included. The infant mortality rate in the study area was 54 deaths per 1000 live births. The risk of dying in infancy was lower for females [adjusted OR (AOR): 0.518, 95% CI: 0.284, 0.945], health deliveries (AOR: 0.429, 95% CI: 0.235, 0.783), infants born to mothers attended ANC during pregnancy (AOR: 0.603, 95% CI: 0.489, 0.744), infants from families with wealth indices of medium (AOR: 0.715, 95% CI: 0.580, 0.882) and rich (AOR: 0.638, 95% CI: 0.425, 0.958) compared with the respective reference categories while it was higher for infants of multiple births (AOR: 2.241, 95% CI: 1.768, 2.841) compared with singletons.Conclusions:Infant mortality rate in the study area, Oromia region, is higher than the national figure. The study found that sex of child, birth type, antenatal care (ANC), place of delivery and wealth index of household were significant determinants of infant mortality. Therefore, concerned bodies should make awareness creation to mothers regarding ANC and encourage them to have ANC follow-up during pregnancy and deliver at health institution to improve the infant survival in the region.