Results of re-operations of 99 adult patients with recurrent supratentorial lobar glioblastomas (60 patients) and anaplastic astrocytomas (39 patients) have been reviewed. In all cases both surgical interventions were performed at the same institute. Age of patients with glioblastoma varied between 19 and 64 and with anaplastic astrocytoma between 21 and 68 years, with a mean value of 48 and 36 years, respectively. The median interval between the first and second operations was 47 weeks for patients with glioblastoma and 83 weeks with anaplastic astrocytoma. The mortality rate of the re-operations was 3%. Following re-operation radio- and/or chemotherapy was applied in most of the cases. Median survival time after re-operation was 18.5 weeks in patients with glioblastoma and 55 weeks with anaplastic astrocytoma. Survival curves were calculated according to Kaplan-Meier method and for statistical evaluation the generalized Wilcoxon test and multiple linear regression method were used. Histologically lower grade tumour at the first operation and longer interval between the two operations proved to influence positively and dedifferentiation of the primary tumour negatively the survival time.