Dural fistulas are acquired arteriovenous shunts, accounting for 10-15p.cent of cerebrovascular malformations. Symptoms are commonly tinnitus or intracranial hemorrhage. Rarely, patients with dural fistulas can present with rapid cognitive impairment. We report two women with rapidly evolving dementia. Cerebral angiography revealed dural arteriovenous fistula, with retrograde drainage into cortical veins, related to thrombosis of both transverse sinuses. Intra-arterial and intra-venous endovascular approaches failed to cure the fistula. Venous embolization via a transcranial approach was required to occlude the fistula, leading to resolution of the symptoms. Dural arteriovenous fistulas may lead to dementia with diffuse white matter changes related to venous ischemia, and must be considered as a reversible cause of vascular dementia. A transcranial approach for venous embolization is sometimes required.