Background: Neonatal hyperbilirubinemia is a serum bilirubin greater than 85 μmol/L (5 mg/dL). It is the yellowish discoloration of the skin, sclera and mucous membranes resulting from deposition of bilirubin. Based on previous studies, ABO incompatibility, sepsis, breast feeding and prematurity were etiologic factors. Objective: To asses magnitude neonatal hyperbilirubinemia and associated risk factors among neonates admitted to neonatal intensive care unit Tibebe Gion Specialize Hospital from July 1/2011 E.C to July 30/2012E.C. Methodology: An institution based Cross-sectional study was conducted on neonates admitted at NICU of TGSH from July 1/ 2011 to July 30/ 2012E.C E.C. From a total of 678 neonates who fulfilled the inclusion criteria, 380 neonates were taken by a simple random sampling. Data on socio demographic characteristics and risk factors were collected by principal investigators and trained health workers. The data were cleared, entered and analyzed using SPSS version21. By descriptive statistics frequency was done and shown with tables and figures. Binary logistic regression analysis were done to identify neonatal hyperbilirubinemia and its associated factors. Results: In this study, 52.9% neonates had hyperbiliubnemia. Two hundred thirty three (61.3%) neonates were male. The most common etiologic diagnosis were sepsis 29.7 % and prematurity 24.5% .SGH, inadequate breast feeding, prematurity, sepsis and age at admission had significant association with neonatal hyperbilirubnemia. Conclusion: The result of this study showed magnitude of neonatal hyperbilirubinemia is high and identified etiologic diagnosis were sepsis, prematurity and ABO incompatablity.SGH and age at admission, sepsis, prematurity and inadequate breast feeding were associated risk factors. Key words: neonate; hyperbilubinemia; risk factors