Although it is one of the older neurophysiologic tests available, the EEG remains an important diagnostic tool in disorders of the central nervous system despite recent advances in diagnostic technology. It is an essential tool in the assessment and detection of seizures. This is especially true when seizures might be clinically unsuspected, and conversely the EEG may prevent the incorrect diagnosis of non-seizure behaviors. When appropriately used, the EEG supports the diagnosis of seizures, can localize the onset of the seizure, delineate an epileptic syndrome, and even aid in choosing appropriate therapy. In addition, the EEG is a useful window for assessing the neurological status in infants who need to be paralyzed. However, the main value of the EEG in young children is its powerful contribution to the assessment of short- and long-term prognosis. Studies have demonstrated that the EEG is a better predictor of outcome than the neurological examination. In effect, this noninvasive test is singularly more valuable in this respect during the first few months of life than at other ages.