The prognosis for patients with malignant astrocytomas is still poor. The identification of groups of patients with good prognostic factors should be helpful in selecting the treatment strategies. In general, important prognostic factors are thought to be the extent of surgical resection required, age, performance status, duration of symptoms, location, and pathological tumor grade. The purpose of this present study is to evaluate the prognosis of patients with complete response (CR), that is, complete disappearance of the tumor mass in the contrast enhancement of computerized tomography (CT) scan after initial treatment. An additional purpose is to examine the effect of factors such as pathological tumor grade, location, age of patient, and the extent of surgical resection in achievement of CR. The subjects of the study were 81 patients with supratentorial malignant astrocytomas (45 males, 36 females) treated with surgical resection and radiochemotherapy in our division since 1980, and followed up for more than 5 years. There were 57 anaplastic astrocytomas (WHO grade III) and 24 glioblastomas (WHO grade IV). The extent of surgical resection and the response to the therapy were evaluated by CT scans. The Kaplan-Meier method was used in generating survival plots. Twenty-two cases (27%) showed CR at the end of the initial treatment, and the other 59 cases (73%) showed Non CR. Fifteen cases (26%) among 57 grade III patients and 7 cases (29%) among 24 grade IV patients showed CR. Tumor locations of CR cases were exclusively superficial with the exception of one case that involved deep structure. Average age of CR cases and Non CR cases were 34.4 and 49.7, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)