Between January 1962 and December 1966, 32 patients with a histologically confirmed diagnosis of astrocytoma Grade 3 or 4 (glioblastoma multiforme) were entered into a cooperative, prospectively randomized study to compare the effects of postoperative, high dose, supervoltage radiotherapy alone (17 cases) versus a similar course of postoperative radiotherapy and concomitant systemic 5-fluorouracil chemotherapy (15 cases). The average survival from diagnosis (incomplete removal) was 11.7 months in the radiotherapy only group and 11.5 months in the combined therapy group. Two patients are still alive, 1 at 37 months treated by irradiation alone and 1 at 26 months who received combined therapy. We conclude that combined therapy with 5-fluorouracil offers no advantage, from the standpoint of duration or caliber of survival, over high dose postoperative radiotherapy alone in the management of patients with glioblastoma multiforme.