OBJECTIVES: True spontaneous intracranial arteriovenous fistulas (AVFs) of posterior circulation are very rare. Clinical entity and natural history of these lesions are not well known. We describe our experience in treating these lesions by microsurgical and/or endovascular techniques. CLINICAL PRESENTATION: Two patients were presented with subarachnoid hemorrhage and one with progressive hearing deficit and tinnitus. Angiograms revealed the presence of intracranial AVFs in all three cases and feeding vessels from the basilar perforator, vertebral artery, and anterior inferior cerebellar artery (AICA), respectively. Venous ectatic changes were also combined in all cases. Surgery was performed via a transpetrosal approach in a case of an unruptured AVF, which was fed by a basilar perforator with venous aneurysmal dilatation in pons. However, afferent vessel to the fistula could not be identified in microsurgical field. Endovascular occlusion was performed successfully 2 months later. In a case of spontaneous vertebral AVF presented with subarachnoid hemorrhage, the fistula was occluded and entangled dilated veins were completely excised via a far lateral suboccipital approach. The last case of AICA origin also presented with subarachnoid hemorrhage died from rebleeding during the preparation of endovascular treatment on the same day of the first ictus. CONCLUSION: Spontaneous intracranial AVFs of posterior circulation showed aggressive behavior. We recommand surgical and/or endovascular treatment for these lesions.