Etiological Parameters in Neonatal Hyperbilirubinemia and Their Predictive Value OBJECTIVE: The main objective of this study was to test the frequency of etiological factors for neonatal hyperbilirubinemia and to estimate their predictive value for the maximum value of the total bilirubin in the serum at the time of diagnosis, as well as for the choice of therapy and the duration of the disease. STUDY DESIGN: This study is organized as a cross-sectional study. PARTICIPANTS AND METHODS: This study included 100 patients born between 2016 and 2022 in Požega who were treated at the Department of Pediatrics of the Požega General County Hospital and were diagnosed with hyperbilirubinemia. Data about hematological and biochemical findings, imaging diagnostic tests, along with the etiological factors which caused hyperbilirubinemia were collected from the medical records, as well as the data on the maximum value of the total bilirubin in the serum at the time of diagnosis, the choice of therapy and the duration of the disease. RESULTS: Out of 100 patients, 66 % were male. Neonatal infection, sepsis, ABO, and Rh incompatibility were the most common etiological factors that caused hyperbilirubinemia. The duration of the disease was the longest for patients with neonatal sepsis and the shortest for those with nonspecific jaundice. Phototherapy was most frequently used on patients without neonatal sepsis. Etiological factors did not have predictive value for the maximum value of the total bilirubin in the serum at the time of diagnosis nor for the choice of other therapies. CONCLUSION: Hyperbilirubinemia is a very common condition among the newborn population which can be caused by many etiological factors, among which neonatal infection, sepsis, ABO, and Rh incompatibility are the most common. The most serious etiological factor is neonatal sepsis which causes the longest duration of the disease.