Seizures in the neonatal period are usually concomitants of serious neurological disease. The convulsive phenomena take certain distinctive and often subtle forms because of the status of the neuroanatomical and neurophysiological development of the neonatal brain. The predominant etiological process is hypoxic-ischemic encephalopathy, but intracranial hemorrhage, intracranial infection, development defects and metabolic disorders are also responsible for a considerable proportion of cases. Prognosis is related primarily to the neurological disease that underlies the seizures. Treatment may be specific for the underlying disorder, e.g., glucose, calcium, magnesium, pyridoxine, but whatever the cause, urgent control of the convulsions is important because they may have deleterious consequences. Phenobarbital is the single, most important anticonvulsant in the management of neonatal seizures.