Brainstem gliomas of children are variably malignant tumors that rarely have been reported to produce subarachnoid dissemination. Nevertheless, during a two-year period, 5 of 15 such patients treated by us developed symptoms of leptomeningeal metastases. The diagnosis of an anaplastic astrocytoma with meningeal gliomatosis was confirmed postmortem in all 5. In 3 children, meningeal symptoms preceded other signs of posterior fossa recurrence. Symptoms of meningeal gliomatosis included local or radiating back pain (5 patients), segmental weakness (3), paresthesia (2), and incontinence (2). Myelography, performed in 4 patients, was the most useful diagnostic technique, disclosing multiple intradural filling defects or a high degree of block in 3 patients. Although the cerebrospinal fluid was abnormal in all 4 examined patients, in only 1 were malignant cells detected. Prolonged survival, which appears to predispose to dissemination of adult malignant gliomas, was not an apparent factor in our patients.