OBJECTIVE To investigate auditory perception development in neonates and correlate it with days after birth, left and right hemisphere development and sex using event-related potential (ERP) technique. METHODS Sixty full-term neonates, consisting of 32 males and 28 females, aged 2-28days were included in this study. An auditory oddball paradigm was used to elicit ERPs. N2 wave latencies and areas were recorded at different days after birth, to study on relationship between auditory perception and age, and comparison of left and right hemispheres, and males and females. RESULTS Average wave forms of ERPs in neonates started from relatively irregular flat-bottomed troughs to relatively regular steep-sided ripples. A good linear relationship between ERPs and days after birth in neonates was observed. As days after birth increased, N2 latencies gradually and significantly shortened, and N2 areas gradually and significantly increased (both P