Vasculopathy is rarely reported in neurofibromatosis type 1, but when it occurs it primarily involves the aorta and its main branches. Among vasculopathies, aneurysmal dilatation is the most common form. Although several case reports concerning aneurysms or pseudoaneurysms of visceral arteries in neurofibromatosis type 1 patients have been reported, there are no reports describing gastroduodenal artery aneurysms associated with neurofibromatosis type 1. We experienced a case of life-threatening duodenal ulcer bleeding from a ruptured gastroduodenal artery aneurysm associated with neurofibromatosis type 1. We treated our patient by transarterial embolization after initial endoscopic hemostasis. To our knowledge, this is the first reported case of its type. High levels of suspicion and prompt diagnosis are required to select appropriate treatment options for patients with neurofibromatosis type 1 experiencing upper gastrointestinal bleeding. Embolization of the involved arteries should be considered an essential treatment over endoscopic hemostasis alone to achieve complete hemostasis and to prevent rebleeding.