We performed electroencephalograms in 32 neonates of intrauterine growth retardation (IUGR) within seven days of birth. EEG findings were compared with those observed in neonatal brain damage. Seven EEGs had a dysmature pattern which is seen in the subacute and chronic stages of prolonged and mild neonatal brain depression, and five had a disorganized pattern which is seen in the subacute and chronic stages of severe neonatal brain depression. The other EEGs had a normal neonatal pattern. Seven neonates who had a dysmature pattern were severe IUGR (< or = 2.5 SD). Their head circumference was retarded at birth, and the S/D ratio of the umbilical artery increased, suggesting chronic brain damage in utero. On the other hand, five neonates displaying a disorganized pattern were preterm IUGR (< 37 weeks). They had NST abnormalities. The abnormal EEG pattern observed in IUGR was similar to that observed in postnatally injured neonates. The abnormalities in EEGs are correlated with the degree of later neurological sequelae. The present study suggested that the EEG of IUGR recorded immediately after birth was useful in evaluating their intrauterine environments and postnatal neurological outcome.