Splenic vein aneurysm (SVA) is extremely rare. Most patients with an SVA have portal hypertension. In this report we describe the first recorded case of intra-abdominal hemorrhage due to rupture of an SVA in a patient without evidence of portal hypertension. A 72-year-old man was admitted to our medical center in a state of shock, with complaints of acute abdominal pain and abdominal distention. Preoperatively, abdominal ultrasonography demonstrated an echo-free space in the abdomen, suggesting the presence of a fluid collection. In addition, computed tomography revealed an enhanced lesion with contrast material in the pancreatic tail. An emergency operation showed bleeding from the SVA near the pancreatic tail. Consequently, a distal pancreatectomy with splenectomy was performed. Histologically the lesion was diagnosed as an SVA surrounded by pancreatic tissue with chronic inflammatory changes. The patient's postoperative course was uneventful.