Superior mesenteric artery aneurysm (SMAA) is a rare entity. Management varies from simple ligation with or without revascularization to endovascular placement of a covered stent graft. The authors report a case of SMAA who presented with retroperitoneal hemorrhage. Diagnosis was made from abdominal computed tomography and angiography. The cause of SMAA was not definitely identified but infective origin was highly suspicious. The patient underwent successful treatment with ligation of the superior mesenteric artery proximal and distal to the SMAA.