Background. Early neonatal mortality remains a significant public health challenge in Ethiopia. Therefore, this study is designed to investigate the magnitude and underlying factors associated with early neonatal mortality among infants admitted to the Neonatal Intensive Care Unit at Hiwot Fana Specialized University Hospital in Eastern Ethiopia. Methods. an institutional-based cross-sectional study was conducted from November 20 to December 20, 2021, by reviewing the medical records of 432 neonates admitted from September 11, 2018, to September 10, 2021. Data were cleaned, entered into Epi Data 3.1, and analyzed using Stata 15. Bivariable and multivariable logistic regression analyses were employed with statistical significance set at a P-value <.05. Results. The study found that the magnitude of early neonatal mortality was 10.6% (95% CI: 8.06, 13.94). The primary contributors to early neonatal mortality was early onset neonatal sepsis (56%), preterm birth (52.2%), and perinatal asphyxia (32.6%). Notably, early onset neonatal sepsis (Adjusted Odds Ratio [AOR] = 2.31, 95% confidence interval [CI]: 1.06, 5.05), respiratory distress syndrome (AOR = 3.98, 95% CI: 1.97, 8.05), and low birth weight (AOR = 3.70, 95% CI: 1.67, 8.18) were independently associated with early neonatal mortality. Conclusion. The study focuses on the significance of early neonatal mortality in Ethiopia, with key factors such as early onset neonatal sepsis, respiratory distress syndrome, and low birth weight contributing to this issue. The advancements in preventive interventions and early management of high-risk neonates offer promise in reducing early neonatal deaths.