Abstract: Objective:To explore the effects of atrial natriuretic peptide (ANP) and antidiuretic hormone (ADH) in plasma on asphyxiated neonates with hyponatremia and its clinical values. Methods: In 40 asphyxiated neonates with hyponatremia and 20 normal term newborn infants, ANP and ADH levels in plasma were measured by radial immunoassay both in acute and recovery phases. At the same time,the effect of transfusion for serum sodium was observed. Results :① the plasma ANP and ADH levels of asphyxiated neonates in acute phase were significantly higher, The more serious the asphyxiated, the highter the ANP and ADH levels,and the lower the serum sodium ( p 0 01). ②In restricting fluids' infants, the serum sodium level recovered normally after birth one week, but in unrestricting fluids' infants the serum sodium was significantly lower. Conclusion:ANP and ADH may be involved in the water and salt metabolism in asphyxiated neonates . It may cause losed natrium and diluted hyponatremia that is more important. The therapy must be to restrict fluid under 30～50ml·kg -1 /d, to give some sodium and frusemide if necessary.