Background: Neonatal jaundice is a common condition in newborns, characterized by the yellowish discoloration of the skin and sclera due to elevated bilirubin levels. Understanding the prevalence and underlying factors of neonatal jaundice in neonatal intensive care units (NICUs) is crucial for effective management and prevention. This study aimed to determine the prevalence and identify the underlying factors of neonatal jaundice among neonates admitted to NICUs in Al-Qalyubia Governorate. Methods: This cross-sectional study was conducted on 3214 newborns admitted in five NICUs in Al-Qalyubia Governorate from March 2022 to March 2023. Neonates aged 1 to 28 days with neonatal jaundice requiring admission were included. Data were collected through detailed history taking, physical examination, laboratory investigations, and the Modified Bilirubin-Induced Neurological Dysfunction (BIND) score. Results: The prevalence of neonatal jaundice among the studied neonates was 31% (995 out of 3214). The most common cause of jaundice was idiopathic(physiological) (56.3%), followed by ABO incompatibility (30%) and Rh incompatibility (8.5%). The majority of neonates were delivered by cesarean section (84.1%), and 82.4% were breastfed. The mean BIND score was 1.96 ± 1.009, with mild acute bilirubin encephalopathy observed in 7.1% of cases. All studied neonates underwent phototherapy, with 52% receiving intensive phototherapy. The mean duration of NICU stay was 4.11 ± 1.12 days. Only one case (0.1%) died during blood exchange. Conclusion: Neonatal jaundice is a prevalent condition in NICUs, with idiopathic (physiological) cause is the most common. followed by ABO incompatibility, then RH incompatibility.