We report the case of a 59-year-old women with a cerebral arteriovenous malformation (AVM) in the right frontal lobe, which was detected incidentally. Additionally, an aneurysm was found at the feeding artery of the AVM. The patient was treated conservatively. Nine years later, the nidus of the AVM was no longer detectable. The angiography showed the associated aneurysm growing irregularly with a daughter sac. The spontaneous occlusion of an AVM and the following progression of an associated aneurysm are rare. The possible mechanisms leading to the occlusion of the AVM and the progression of the associated aneurysm are discussed. (c) 2014 by National Stroke Association