Survival of glioblastoma patients can be double by postoperative radiation but nevertheless rarely exceeds one year. It is therefore desirable to minimize treatment time and hospitalisation. Aim of our study is to investigate the feasibility of a reduction of treatment time by accelerated fractionation. Out of 110 patients treated for glioblastoma from 1975 to 1988 in our institution postoperative radiation was performed in 79 patients using three different fractionation schedules: 60 Gy in six weeks, single fractions 2 Gy (n = 38), 35 Gy in two weeks, single fractions 3.5 Gy (n = 27), 45.5 Gy in 2.5 weeks, single fractions 3.5 Gy (n = 14). No statistically significant differences in both the mean overall and disease free survival were evaluated between the three groups. The larger fraction size was well tolerated and no relevant increase of early or late adverse reactions occurred. As the duration of treatment can be reduced from six to two weeks, this accelerated fractionation schedule seems to be a reasonable alternative to conventional fractionation.