During the 13-year period 1964 through 1976, 37 patients less than 20 years old with an intracranial, parenchymal arteriovenous fistula were seen at the Mayo Clinic. The most frequent mode of presentation was hemorrhage or seizure. Other than angiography, computed tomography with contrast enhancement was the most helpful diagnostic test. Surgery was restricted to patients with intraparenchymal hematomas, intractable seizures, or subarachnoid hemorrhage with accessible lesions and to 1 infant with a massive, symptomatic malformation. Surgery generally was tolerated well, with reversal of most acute focal neurological deficits related to hematomas. In the nonsurgical group, follow-up revealed a fairly stable neurological status during the period of the study.