Background: In Ethiopia, the neonatal mortality rate has not shown significant changes over time and is among the highest in the world. Exploring the magnitude and the causes of neonatal mortality in the hospital where neonatal intensive care unit is functioning could be supremely important to step towards improving the quality of neonatal care services. Therefore, this review aimed to explore the pooled magnitude and determinates of neonatal mortality in the neonatal intensive care unit hospitals in Ethiopia. Methods : The research team retrieved global peer-reviewed journal articles available as electronic databases including PubMed, Popline, and Scopus databases. Google Scholar, institutional repositories, and Google were used to retrieve grey literature. Random-effects meta-analysis model was used to pool the estimates of the magnitude of mortality among studies. The results were presented as the pooled estimates (odds ratio and proportion) with 95% confidence intervals, at less than 0.05 significant levels. Results: In this review, 10 studies were included with a total of 8,729neonates. Of these, 1,779 (20.4%) neonates died in the neonatal intensive care unit. The pooled neonatal mortality rate was 19.0% (95% CI: 14.0-25.0). The neonatal mortality is three times higher among early age (OR: 2.80; 95% CI: 1.45-5.40) and preterm newborns (OR: 3.27; 95% CI: 2.12-5.07) than their counterparts. Early age of the newborn, prematurity, low birth weight, perinatal asphyxia, mode of delivery, hypothermia, late initiation of breastfeeding, and having antenatal care visits were the main determinants for neonatal mortality. Likewise, perinatal asphyxia, hyaline membrane disease, respiratory distress syndrome, and prematurity were identified as the most determinant and statistically associated with the death of premature neonates admitted to intensive care units.Conclusion: Neonatal mortality in the intensive care unit is high. It is unacceptably high amongst early and preterm neonates. Special care for preterm and early age newborns, timely initiation of breastfeeding, exclusive breastfeeding, and appropriate mode of delivery, essential obstetric and newborn care, and promoting antenatal visits are recommended to reduce neonatal mortality.Protocol registration: The protocol was registered at the International prospective register of systematic reviews (PROSPERO) with registration number CRD42019123195.