Background:Neonatal hyperbilirubinemia (NH) affects over 80% of premature babies & 60% of full-term babies in the first week of life. There are two forms of neonatal hyperbilirubinemia: conjugated & unconjugated. Unconjugated forms can cause  bilirubin encephalopathy & kernicterus in extreme cases, while conjugated forms are thought to be a result of a systemic sickness. Babies born prematurely are at a higher risk of hyperbilirubinemia due to bilirubin-induced brain damage compared to their term counterparts.  Aim and objectives: The study aims to assess the effect of phototherapy on liver enzymes, renal functions, in NH patients before and after phototherapy . .Subjects and methods: This was an observational cross-sectional study that was performed at  neonatal intensive care unit (NICU) Al- Hussein university hospital. It included 100 term infants of both sex that received phototherapy for management of neonatal indirect hyperbilirubinemia. When indicated according to Bhutani Nomogram curve.  Result: There is no statistically significant difference was found between group I that treated by conventional phototherapy only and group II that treated by intensive then conventional phototherapy regarding maternal age , ABO blood groups and Rh  status maternal comorbidities like gestational HTN or diabetes , gestational age , onset of jaundice.  Also Both therapy groups reduced total and direct bilirubin significantly (Paired sample t test, P = 0.000). Group II had a greater total bilirubin reduction than group I (Independent sample t test, P = 0.001). Both therapy groups had significant ALT, AST, ALP ,urea and creatinine reductions (Paired sample t test, P = 0.000). Conclusion: As regard the effect of Phototherapy on liver enzymes and kidney functions , our results showed a statistically significant reduction in ALT, AST, ALP ,urea and creatinine in both treated groups. Keywords: neonatal intensive care unit (NICU), Neonatal hyperbilirubinemia (NH), total serum bilirubin (TSB)