PURPOSE: Children with recurrent or progressive central nervous system (CNS) tumors have an unfavorable prognosis. Based on Pediatric Oncology Group (POG) institutional pilot data, low-dose oral methotrexate (MTX) was studied. METHODS: Eight dosages of MTX 7.5 mg/m2 every 6 hours were administered on a weekly schedule for as long as 18 months. Patients in six different brain tumor strata were accrued. RESULTS: The response rates (complete or partial responses) were as follows: astrocytoma 2 of 10, malignant glioma 1 of 19, medulloblastoma 0 of 18, brainstem tumor 0 of 12, ependymoma 1 of 7, and miscellaneous histologic types 0 of 12. The main toxicities, mucositis, myelosuppression, and hepatic transaminase elevation were considered tolerable. CONCLUSION: Low-dose oral MTX showed no significant activity against malignant glioma, medulloblastoma, brainstem tumors, and miscellaneous histologic types. Indeterminate but low response rates were observed in children with astrocytoma and ependymoma. This regimen will not be recommended for front-line therapy.