A retrospective survey has been carried out on 56 children with shunted hydrocephalus either with a primary idiopathic cause or as a result of a low spina bifida complex. In all 56 children, a separate reservoir has been inserted at some stage in the management of their hydrocephalus.There was no mortality. Morbidity was not increased from CSF infection or shunt blockage. There was less chance of the initial shunt blocking and there was a lesser incidence of visual and schooling handicap. Double cortical puncture did not result in an increased incidence of hemiplegia or epilepsy.We conclude that a separate reservoir greatly eases the managment of these children and does not cause significant increased morbidity.