Urinary epidermal growth factor (EGF) excretion in normal newborn as well as neonates with asphyxia was investigated by using radioimmunoassay, and serum creatinine (Scr) levels determined at the same time. The results showed that in severe asphyxia group the ratio of urinary EGF to urinary creatinine (Cr) (EGF/Cr), an index reflecting EGF excretion, was decreased on the first day (P < 0.05) and reached the lowest level on the third day (P < 0.01). However, EGF/Cr values were decreased only on the third day in neonates with mild asphyxia (P < 0.05). On the seventh day, EGF/Cr values of neonates with asphyxia rose to normal. There were a negative correlation between urinary EGF/Cr and Scr. It is suggested that EGF may play a role in the repair of acute renal injury after asphyxia and the detection of urinary EGF concentration is useful in the judgment of severity of renal injury and in the evaluation of the recovery of renal tubule after injury.