Neurological and developmental outcome was assessed in 131 survivors of neonatal seizures aged 1 to 5 years who had been treated in a single intensive care unit from 1976 to 1979. Half the children had been born at less than 37 weeks' gestational age, and 28% at 31 weeks or less. Fifty-one children were normal on examination, 17 had minor abnormalities, 25 had moderate disabilities, 30 had severe disabilities, 6 had died because of profound neurological deficits, and 2 could not be located. Recurrent nonfebrile seizures had developed in 26 children. Most children with motor handicaps or visual loss were intellectually retarded, but 10 of 15 children with bilateral hearing loss were intellectually normal. Of 77 children whose seizures were caused by a hypoxic-ischemic insult, 41 developed moderate or severe disabilities. As determined by multivariate analysis, significant neonatal predictors of poor outcome in this group included seizures with late onset, tonic seizures, and seizures lasting for many days. Although seizure frequency and neonatal mortality associated with seizures were greatest in very premature infants, the outcome in premature infants who survived was not significantly different from that of term infants.