Background:Early diagnosis and treatment are very important to reduce the rates of morbidity and mortality related to Inborn errors of metabolism .The present study aimedto detect the inborn errors of metabolism early among neonates.This was a cross sectional study was carried out at neonatal intensive care unit in pediatric department at Zagazig university children hospital. This study involved 114 neonates who were subjected to full medical history, thorough clinical examination and laboratory investigations which included Complete blood count, Coagulation profile ,C-reactive protein ,procalcitonin, Liver and renal function tests , Serum levels of electrolytes, Plasma ammonia and lactate, Urine organic acid analysis, Extended metabolic screening, Blood gas and serum anion gab and Blood glucose level. Results:About 53.5% of the studied groups were males and 46.5% were females. As regards mode of delivery 74.6% were by CS and 25.4% by NVD. Also, 30.7% had positive consanguinity, 12.3% had sibling death, and 3.5% have similar condition. History of abortion was found in 22.8% and genetic disease was in 2.6% of the studied group. The main clinical presentations among the studied group were RD, Encephalopathy and hypotonia. Only 6.1% of the studied group had positive culture metabolic acidosis was detected only in 9.6% of the studied group. About 90.4% of the studied group was alive and 9.6% were died. Conclusion: IEM disorders are not rare disease in high-risk neonates with attentions to consanguinity which is a common tradition in our country. The manifestations of metabolic disorders are common, and many physicians misdiagnose them as they are unaware about these disorders.