The Swedish Cancer Registry, in a linkage with the Swedish Registry of Statistics, was used to trace all patients operated on in Southern Sweden for histopathologically verified malignant primary central nervous system tumors during the years 1958 to 1975. Patients surviving 10 years after the operation were identified, and their original surgical specimens were reexamined. Six (0.5%) of 1147 patients were shown to have survived for between 12 and 28 years after surgery for supratentorial astrocytomas grade III and IV. All six patients are in good condition, without signs of tumor recurrence. The only obvious common denominator for the survivors is their youth at operation. Three patients were 7 to 11 years old at surgery, and none was older than 38 years. It is concluded that a cure may be possible in exceptional patients with the "incurable" astrocytoma grade III and IV.