Seventeen infants with central nervous system malignancies, all with tissue diagnosis, were treated with the combination chemotherapy nitrogen mustard, vincristine, procarbazine and a steroid (MOPP) as primary therapy following surgery. Diagnoses include: 7 astrocytomas (grade: 3-I, 3-II, 1-III), 6 medulloblastomas, 2 ependymoma/astrocytoma mixed, 1 ependymoma and 1 primitive neuroectodermal tumor. Fourteen were under 2 years of age, 2 between 2 and 3 years of age, and 1 between 3 and 4 years of age. Fifteen responded and 2 failed. Of the responders, 6 are in continuous complete remission (median duration 28.9+ months) and 9 are in relapse (median duration of remission 10.3 months). Of the 2 patients who failed and 9 who relapsed, 4 expired and 6 are living in partial or complete remission. We conclude that MOPP therapy is well tolerated, has effectiveness, and allows postponement of potentially debilitating radiotherapy in infants with brain tumors.