In this prospective study, we investigated the effects of hypofractionated radiotherapy for patients with high-grade gliomas. About 31 patients with glioblastoma multiforme or anaplastic astrocytoma were studied between October 2003 and December 2004. Hypofractionated radiotherapy (3 Gy/fraction/day) was delivered to a total dose of 45 Gy in 15 fractions in 10 patients (32%) who had total excision before radiotherapy and to a total dose of 54 Gy in 18 fractions in 21 patients (68%) who had subtotal excision or biopsy alone. Sex, age, type of surgery, tumor grade, Karnofsky performance status, time between surgery and initiation of radiotherapy, and total radiotherapy dose were analyzed as potential prognostic factors for survival using the univariate log-rank method. The median follow-up was 15 months (4-16 months). A total of 15 patients (48%) died of their illness; 16 patients (52%) were still alive at the last follow-up. The median survival time was 8 months. Actuarial 1-year overall survival was 40%. Type of surgery, timing of radiotherapy after surgery, and initial Karnofsky performance status were significant prognostic factors for survival. No grade 3-4 acute or late neurotoxicity was observed. The tolerance of patients to hypofractionated RT was not different from that for con- ventional radiotherapy. This treatment schedule can be used for patients with high-grade gliomas. Future investigations are needed to determine the optimal fractionation for high-grade gliomas.