Eight patients with recurrent medulloblastoma were treated with a chemotherapy regimen consisting of vincristine, BCNU, dexamethasone and intrathecal and intermediate dose intravenous methotrexate (500 mg/m2). Five also received local low dose radiotherapy (RT). All 8 patients responded to treatment; 6 completely and 2 partially. These latter 2 were in their second and third recurrences. Three remain in remission. The median duration of response was 18.8 months, and median time from start of chemotherapy to death was 32 months using the Kaplan-Meier technique. In addition, 9 other patients with newly diagnosed medulloblastoma were treated with craniospinal radiation and the same adjuvant chemotherapy as above. The first 5 patients also received intraventricular methotrexate and/or intravenous BCNU during radiotherapy. The toxicity in the 5 patients was very severe. There were three toxic deaths, one death from cancer; one patient survives disease-free, but he is demented. With the discontinuance of intraventricular methotrexate and the postponement of myelo-suppressive chemotherapy until after the completion of radiotherapy, the regimen has been well tolerated. All 4 patients treated this way remain alive, well, and disease-free at intervals up to 36 months. We conclude that recurrent medulloblastomas are sensitive to multiagent chemotherapy and that prolonged remissions may occur. With primary adjuvant chemotherapy, extreme caution with myelo-suppressive drugs must be exercised during the period of craniospinal radiotherapy. We also do not recommend the use of intraventricular methotrexate. When these two criteria were followed, the preliminary results with adjuvant chemotherapy appear encouraging.