The authors report a case of spontaneous occlusion of an arteriovenous malformation (AVM) verified by the second angiography performed 3 days after the initial one. This 65-year-old man had a sudden attack of headache, nausea, and vomiting and was admitted to our hospital next day. On admission, CT scan showed subcortical hemorrhage in the right temporo-parietal area and right CAG showed a small AVM in the same area. The main feeder was a MCA distal branch and the drainer joined Labbe's vein. Repeated angiography 3 days after initial one failed to demonstrate the AVM. Craniotomy was performed and thrombosed AVM was totally removed. Mechanism for disappearance of the malformation is assumed to be acute thrombosis due to intracranial hemorrhage and arteriosclerotic change. The literature is reviewed.