From September, 1972 to December, 1976, 102 consecutive patients operated on for glioblastoma multiforme were randomized, after total or subtotal tumor resection, to receive irradiation alone, irradiation plus BCNU or irradiation plus CCNU. BCNU and CCNU adjuvant chemotherapy was repeated every 6--8 weeks as long as the patients remained in complete remission. Patients were comparable for median age, type of surgery, and histological grade III and IV. Radiotherapy was administered at the tumor dose of about 5000 rads in all three groups. The percent of optimal dose administered was 96% for BCNU and 93% for CCNU. In the group treated with radiotherapy alone (32 cases) the median survival was 10.5 months, while in the groups treated with BCNU (34 cases) and CCNU (36 cases) the median survival was 12 and 16 months, respectively. Both relapse-free (P = 0.05) and total survival (P = 0.03) were significantly improved only in patients who were treated with radiotherapy plus CCNU compared to patients receiving radiotherapy alone after surgery. Present results show that in resectable glioblastoma multiforme, a slightly improved survival rate can be achieved by the prolonged use of adjuvant CCNU following maximal surgical resection and radiotherapy. The cure rate was not improved.