Spontaneous regression of an arteriovenous malformation is rare. When complete or partial regression occurs, an associated factor is usually involved, such as intracranial hemorrhage, surgery, radiation therapy, or a new neurological deficit. Another case in which the resolution was totally spontaneous is presented here. We discuss the importance of transcranial doppler revealing the hemodynamic changes in the cerebral arteries in the presence of an AVM and when the latter is thrombosed. Several mechanisms for regression are considered, and we focus on the dissection of the afferent vessel, pointing out the role of such an event in the natural history of AVM.