INTRODUCTION: Peripancreatic arterial pseudoaneurysm is a rare but potentially lethal complication of severe acute pancreatitis because it can massively bleed into the gastrointestinal tract. Since surgical treatment of such cases has a high mortality, percutaneous angiographic embolization of bleeding artery has recently been advocated as an alternative therapy. We report a case of acute pancreatitis complicated by gastrointestinal hemorrhage due to a ruptured gastroduodenal artery pseudoaneurysm, in which hemostasis was achieved by transcatheter arterial embolization. CLINICAL CASE: A 65-year-old woman was transferred from another hospital with a diagnosis of severe acute biliary pancreatitis, and having had hematemesis. Upper GI endoscopy detected bleeding from the papilla of Vater, and CT showed hemorrhage in a pseudocyst at the pancreatic head. Angiography revealed active bleeding from an arterial pseudoaneurysm of the gastroduodenal artery: hematemesis was considered to result from rupture of the pseudoaneurysm (hemosuccus). Transcatheter arterial embolization was performed by a 2-step procedure, both through the celiac trunk, that was stenotic, and through the superior mesenteric artery, and hemostasis was achieved. CONCLUSIONS: We conclude that transcatheter arterial embolization is a minimally invasive and highly effective treatment for acute bleeding from a ruptured pseudoaneurysm secondary to acute pancreatitis.