A 43-year-old patient with a basilar apex aneurysm had a 4.5-mm x 14-mm Enterprise stent placed from the midbasilar artery to the left P1 segment of the posterior cerebral artery. The patient experienced vertigo 4 months after stent placement and 1 week after stopping clopidogrel. At 5 months postembolization, angiography showed stent migration into the proximal basilar artery. This is the first described case of the spontaneous delayed migration of a self-expanding intracranial microstent.