Summary:Pediatric brain tumors differ from adult brain tumors in several important ways: (a) the tumor types and sites differ, with low-grade gliomas being more common than high-grade, and posterior fossa tumors occurring as commonly as supratentorial tumors; (b) the extent of resection is an important determinant of outcome for many tumor types; (c) chemotherapy is often used postoperatively to defer and occasionally to avoid irradiation; and (d) the prognosis is substantially better for many tumor types. Extent of resection appears to correlate with prognosis for children with supratentorial low-grade and highgrade gliomas and primitive neuroectodermal tumors (PNETs), and for those with infratentorial astrocytomas, ependymomas and some medulloblastomas. Postoperative staging is important for children with supratentorial malignant gliomas or PNETs, those with germ cell tumors and those with posterior fossa ependymomas and medulloblastomas. Chemotherapy is now commonly administered prior to postoperative irradiation for children with malignant tumors, and is used to delay significantly or avoid radiotherapy for children younger than 3 years old and for patients with low-grade gliomas, especially those in the optic chiasm and hypothalamus. Because of the risks of conventional external beam irradiation, increasing numbers of tumors are being treated with focused irradiation, using either stereotactic radiosurgery or intracavitary irradiation. The prognosis of children with malignant gliomas and medulloblastomas has improved.