We documented seizures in 33 of 68 (48.5%) children with congenital hydrocephalus not associated with myelomeiningocele. Mental retardation (MR) and CNS malformations correlated with seizure occurrence, age at shunt insertion and number of shunt revisions and infections were not significant variables in predicting seizures. Of 11 patients seizure free for 2 or more years on medication, six had therapy discontinued without seizure recurrence. Among those 33 children with seizures, 14 (42.4%), including five who had failed withdrawal of medication, have adequately control1ed seizures on anticonvulsants. Frequent convulsions despite treatment occur in 13 (39.4%) of the 33 children with seizures. Absence of MR, older age and nonparoxysmal EEG at seizure onset, and absence of CNS malformation correlated with seizure remission. Longer time without seizures while on medication did not predict successful discontinuation of therapy. In contrast, MR correlated significantly with seizure recurrence following cessation of treatment. Our study indicates that medication can be safely discontinued in children with congenital hydrocephalus who are of normal intelligence and have been seizure free on anticonvulsants for 3 years.