The correlation between EEG and CT scan was studied in 57 full-term newborn infants with various neurological abnormalities, in order to clarify pathological processes underlying EEG abnormalities during the neonatal period. The relation between EEG and CT findings changes with the time elapsing after the acute phase of the perinatal brain insult. The same EEG pattern was associated with different CT findings of perinatal brain injury were usually associated with complete obliteration of cerebrospinal fluid spaces, a phenomenon considered to reflect severe brain swelling. Milkdly and minimally depressed EEGs in the acute phase were usually associated with localized decreased brain density, which is thought to represent localized edema. Moderately depressed background EEGs in the first week were associated with normal CT scans in most cases, although mild localized edema did not produce significant changes in the background EEG in some cases. In contrast to perinatal brain lesions, CT scans were not always well correlated with background EEGs in congenital cerebral dysplasia and intracranial hemorrhage, although the EEG was an useful adjunct to the CT scan in the diagnosis and prognostication of these disorders.