We reviewed the medical records of 218 episodes of status epilepticus in 193 children who were admitted to the hospital between 1983 and 1987. Of the episodes, 61% were in boys and 39% in girls, with an age range of 1 month to 14 years (average, 3.2 years). The majority of episodes (73%) occurred in patients who were less than 5 years old, with 61% less than 3 years old and 28% less than 1 year old. Status epilepticus as the initial seizure occurred in 71% of episodes. In patients under 1 year of age, 75% of episodes were associated with acute causes (bacterial meningitis in 28% and electrolyte disorders in 30%), and 23% were idiopathic (19% associated with fever). In children less than 3 years old, 47% of episodes had an acute cause, 9% had a previously known seizure disorder, and 32% were idiopathic (30% associated with fever). In patients older than 3 years, 28% of episodes were associated with acute causes, 38% were known epileptics, and 13% were idiopathic (11% had fever). Overall mortality was 6%, with 1% of all episodes ending in death during the presenting seizure. We conclude that the etiology of status epilepticus is age related, with acute causes being more common in patients with a younger age at presentation. When our data are compared with other large studies in children, it appears that mortality associated with status epilepticus has decreased.