Neonatal hypoglycemia is a common metabolic problem. The definition and clinical management of neonatal hypoglycemia remains controversial. The concerned reasons are mainly as follows:the course of a physiological decrease and recovery in the level of blood glucose is usually existed in newborn infants after birth;asymptomatic hypoglycemia(many newborn infants' blood glucose level is very low but without any clinical signs or symptoms);and the lack of the complete comprehension for the relationship between neonatal hypoglycemia and the long-term neurologic prognosis. The review describes the etiology,definition and clinical management of hypoglycemia in newborn infants.