Preliminary results of superfractionation in the treatment of glioblastoma led to a randomized trial consisting of 76 patients. All patients received whole brain irradiation followed by a 1000 cGy boost to the primary site. Thirty-four patients received standard daily treatment to 4000 cGy, whereas 42 patients received superfractionated radiation, treating three times a day to a total dose of 4760 cGy. No significant difference was found between the 5-year survival of the superfractionated group and the standard treatment group. Early reactions were greater for superfractionation whereas late effects were less.