A review of the most recent 23 cases of benign intracranial hypertension (BIH), admitted to the War Memorial Children's Hospital in London, Ontario, provided a compendium of the clinical manifestations of this disorder in children and adolescents. Although CT scanning lets one feel more secure in making such a diagnosis, pitfalls still exist. The sex ratio was 11 males to 12 females. Age groupings were: 0-6 years (2 patients); 7-12 years (10); 13-17 years (11). No postviral etiologies were encountered in patients more than 13 years of age. In only 6 cases could no definite etiology be established. Of great importance was the recognition of the condition in 12 patients who did not have papilledema. Elevated intracranial pressure was proven in 8 of these by lumbar CSF pressure monitoring, in 1 by lumbar punctures and in 1 infant with split cranial sutures. Absence of papilledema was confirmed by ophthalmological examination. Transient visual obscurations were very common in this group. In 6 patients, persistent signs and symptoms in spite of vigorous drug therapy prompted lumboperitoneal shunting, with immediate relief of symptoms in all. In only 1 case has the diagnosis of BIH proven to be in error. A warning leak from an aneurysm caused papilledema and headache, and a normal CT scan supported the diagnosis until the patient had a major hemorrhage weeks later. BIH has a variety of causes in children and adolescents, and papilledema is not a prerequisite for diagnosis.