To determine effects of surgical treatments on the quality and duration of survival following tumor recurrence and to analyze prognostic factors that may affect the outcome, we have reviewed our experience with reoperations for 43 patients having recurrence with malignant histologic findings among 188 cases of supratentorial glioblastoma multiforme (GM), anaplastic astrocytoma (AA) and low-grade astrocytoma (LGA) (27 of 77 patients with GM, and 16 of 42 patients with AA) since introduction of computed tomography (CT) in May, 1976. Using CT and/or more recent magnetic resonance imaging (MRI), the regrowth patterns of tumor recurrence were examined with aspect of local extension, non-contiguous or remote metastatic invasion, and tumor cell dissemination through cerebrospinal fluid. MRI can provide more significant informations on the selection for reoperation in terms of recognition of the developmental features. In most of the patients who underwent reoperations at recurrence, surgically accessible components of the lesion were shown to cause neurological deficits as a result of compression rather than infiltration of functionally important areas. Reoperations thus might be achieved with acceptable mortality and morbidity. In contrast, patients with tumors in inaccessible areas of the central nervous system received additional chemotherapy and/or interferon administration. Indications for re-irradiation of the recurrence is also discussed.