After the study of over 300 angiograms of supratentorial cerebral arteriovenous malformations (AVM's), the authors have formulated an anatomical grading scheme of I to IV to correspond to the degrees of surgical difficulty for total obliteration. The grading is based upon the number of directly participating arteries for which there is a standardized nomenclature. Occasionally, allowance for clinical grading, in addition to this anatomical grading, must be made. Also, for the anticipation of morbidity, but not mortality, the location of the lesion is important. The authors present the postoperative results in a series of 49 patients to demonstrate the clinical usefulness of the grading scheme.