A retrospective analysis was performed on 66 patients with anaplastic astrocytoma (AA) and 177 patients with glioblastoma multiforme (GM). The prognostic importance of age, performance status, tumour location, extent of surgery and radiation treatment was studied. Radiation therapy gave a significant improvement in survival in both AA (p less than 0.003) and GM (p less than 0.002), but was given only to patients in a good neurological condition. Both younger age (p less than 0.003), and good preoperative performance status (p less than 0.002) were associated with a longer survival in AA, but not in GM. Extensive surgery was correlated with a better immediate postoperative performance, a lower one-month mortality rate and a longer survival, in both AA and GM. There was no relationship between preoperative neurological function status and the extent of surgery. Because of the retrospective nature of this study, the conclusion is that performing extensive surgery instead of limited surgery does not lead to more deterioration in postoperative neurological function.