Between 1975 and 1989, 98 children with brain tumours under the age of three at time of diagnosis were entered into a retrospective study. Twenty of them are alive and free of tumour more than five years after treatment and were evaluated in this study. Thirteen tumour localizations were infratentorial and 7 were supratentorial. A histological examination was performed in 15 patients: 5 ependymomas, 6 medulloblastomas and 4 astrocytomas were identified. Fifteen patients underwent surgical removal of tumour, all but one received radiotherapy and 8 were given chemotherapy. Only two children have not late effects. Analysis of long-term sequelae in survivors showed central endocrinopathies in 14 (70%), a neurological handicap in 13 (65%) and impaired cognitive functions in 17 (85%). Irradiation was clearly responsible for mental sequelae in 7 patients and endocrinopathies in 6 patients. The other possible causes are tumour injury, hydrocephalus or surgery. The risks incurred with radiotherapy and advances in infant brain tumour therapy are discussed.