Superior mesenteric arteriovenous fistulae are rare. A 32-year-old woman presented with abdominal pain. The angiography showed that the superior mesenteric vein was aneurysmal. The patient underwent coil embolization, during which a balloon catheter was inflated before the fistula for the protection of coil migration with a high blood flow. After the balloon inflation, one 8-mm and two 7-mm coils were deployed at the fistula site. The final angiography showed successful embolization with no visualization of the fistula and the aneurysmal vein.