A variety of therapeutic options are available for managing arteriovenous malformations(AVM's) including microsurgical resection, embolization, stereotactic radiosurgery or a combination of these treatments. The primary advantages of neurosurgical resection include immediate and almost certain cure, immediate elimination of the risk of hemorrhage, and the absence of longterm delayed complications. Surgery, however, is more invasive than other therapeutic options and is associated with the potential for perioperative morbidity or mortality. A series of 42 patients undergoing microsurgical resection of AVM's of the brain between January 1990 and March 1998 were analyzed for complications and postoperative outcomes. Twelve patients(28.6%) had complications. There were 5 deaths(11.9%) which were thought to be caused by increased intracranial pressure(3 cases), venous infarction(1 case) and postoperative hemorrhage(1 case). Other nonfatal complications were 3 cases of motor weakness, a case of visual field defect following occipital lobe retraction, a case of dilated cardiomyopathy in children and two cases of new onset of seizures. All cases were graded according to the Spetzler-Martin classification. There were six cases of complications in 22 patients with Grade I AVM'(22.7%), three cases of complications in 10 patients with Grade II AVM'(30.0%), one case of complications in 7 patients with Grade III AVM'(14.2%), no complications in 1 patient with Grade IV AVM', and two cases of complications in 2 patients with Grade V AVM'(100%). The various components of the AVM' grading system were analyzed for the ability to predict complications, but there was no statistical significance in this study. The preoperative Glasgow coma scale accurately correlated with the incidence of postoperative complications(p=0.004).