Background: Neonatal hyperbilirbinemia (NH) is a recognized cause of brain damage andrnbilirubin encephalopathy resulting in long-term sequel like sensory-neuronal hearing loss in thernsurvivors and death.rnObjective: To assess magnitude and associated factors of NH among neonates admitted atrnneonatal NICU from September 11/2014 to September 11/2016 in TASH.rnMethodology: Retrospective cross sectional study was conducted on neonates admitted at NICUrnof TASH and 356 neonates were systematically selected among all admitted neonates. Study wasrnconducted from January 2017 to June 2017. Supervisors and data collectors were BSc healthrnprofessionals. Pre-test was conducted on 5% of sample before the starting of actual datarncollection. Checklist was adopted and modified from literatures to collect data. Supervisors werernchecked the collected data daily for completeness. Data was first entered to Epi Info version 7rnand exported to SPSS version 20.0 to clean and analyze data. Relation between dependent andrnindependent variables were assessed and presented using odd ratios and confidence intervals.rnStatistical association was considered as significant if p-value was less than 0.05. Ethicalrnclearance for the study was received from Addis Ababa University, College of Health Sciences.rnA formal letter was written to TASH and permission was secured at all levels.rnResult: Medical record of 356 neonates were reviewed and 160(44.9%) of them developed NH.rn89(25%) of males and 71(19.9%) of females were developed neonatal hyperbilirubinemia. Theirrnserum bilirubin level was from 5.6mg/dl to 77.7mg/dl. Among associated factors of NH: ABOrnincompatibility 57(35.6%), sepsis 30(18.8%), idiopathic cause 22(13.8%), breast feedingrnjaundice 16(10%) and Rh isoimmunization 14(8.8%). Age of neonates was significantlyrnassociated with neonatal hyperbilirubinemia in logistic regression.rnConclusion and Recommendation: Magnitude of neonatal hyperbilirubinemia in this study wasrnnear to half of selected neonates. Among identified associated factors of NH, ABOrnincompatibility and sepsis were the leading cause. So, early prevention and timely treatment ofrnNH is important since it was a cause of long term complication and death in neonates.rnKeyword: Magnitude, Neonatal hyperbilirubinemia