Twelve consecutively diagnosed children with brain tumors, ages 7 to 27 months, were treated by a combined-modality approach featuring aggressive surgical resection followed by chemotherapy and delayed irradiation. Patients received multiple clinical neurologic examinations and psychological evaluations, as well as diagnostic imaging studies, to monitor the efficacy of chemotherapy and toxic effects of therapy. Six of the eight children with residual tumor evident postoperatively on computed tomography scans had objective responses to chemotherapy. The efficacy of chemotherapy was further demonstrated by the lack of disease progression for 7 months or longer in eight children, seven of whom remain free of tumor 19 to 57 months (median, 28 months) from the date of diagnosis. The neurologic status of ten patients improved during treatment. Developmental progress was normal in two, low average in three, and frankly deficient in four of ten children formally evaluated. These results indicate that postoperative chemotherapy, added to a regimen of surgical resection and delayed irradiation, prolong survival with only minimal short term neurotoxicity in the majority of very young children with malignant brain tumors.