Controversy exists as to whether sinus thrombosis is the cause or the result of dural arteriovenous fistula (DAVF) and to whether DAVF are congenital or acquired lesions, especially in children. An infant presented with rupture of an anterior communicating artery aneurysm diagnosed with computed tomography angiography and catheter angiography. Pretreatment hospital course was complicated by extensive dural sinus thrombosis. Subsequent arteriography showed a new adult-type dural arteriovenous fistula to the previously thrombosed right sigmoid sinus. This is the first report of definitive angiographic documentation of the development of an adult-type DAVF after recanalization of a thrombosed dural sinus in a child. This case confirms the acquired etiology of at least one type of DAVF in children, even at this young age. We review the previously documented cases of formation of DAVF subsequent to sinus thrombosis with serial angiography in adults.