Introduction: Continuous renal replacement therapy (CRRT) is useful modality for the critical care of neonates with hyperammonemia caused by inborn errors of metabolism (IEM), which can lead to accumulation of toxic metabolite and poor outcomes. Early treatment of CRRT for IEM may decrease mortality and morbidity in neonates with IEM. However, there was little data for the clinical outcomes in neonates with IEM who underwent CRRT. The aim of this study is to evaluate the clinical outcomes and the prescriptions of CRRT to effectively reduce the serum levels of ammonia in neonates with hyperammonemia. Method: The medical records of 13 Korean neonates with IEM who underwent CRRT for hyperammonemia from January 2008 to December 2016 in Samsung medical center were retrospectively analyzed. The data included demographic information, laboratory results, and CRRT parameters. Result: The median age of neonatal intensive care unit (NICU) admission due to hyperammonemia was 4 days, and 3 patients were preterm babies. Male to female ratio was 2.3:1. The final diagnosis for hyperammonemia included ornithine transcarbamylase deficiency (n=4), citrullinemia (n=4), carbamoyl phosphate synthetase deficiency (n=2), propionic academia (n=2), and long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (n=1). The median age at the time of CRRT initiation was 5 days after birth. All patients received continuous veno-venous hemodiafiltration. Blood flow rate ranged from 7 to 14 ml/kg/min. The median ultrafiltration rate (UFR) at the initiation of CRRT was 2,200 ml/kg/hour, and increased up to the median levels of 2,990 ml/kg/hour. The median duration of CRRT was 4 days. The median plasma ammonia level at CRRT initiation was 1115.8 umol/L. The median value of estimated half time for ammonia level by Gnu plot program was 20.6 hour. The median ammonia levels after 24 and 48 hours of CRRT were 237 and 194 µmol/L, respectively. Five patients restarted CRRT because of rebound hyperammonemia after stopping CRRT. Duration of hospitalization ranged from 4 to 86 days, and the survival rate during hospitalization was 85%. Conclusion: This study suggested that CRRT could be a therapeutic option for neonates with IEM. However, the further study for the optimal CRRT prescriptions to rapidly decrease the ammonia level and prevent the rebound hyperammonemia is necessary.