A lower abdominal tumor with thrill and bruit was pointed out in a 59-year-old female. Angiography showed a pelvic arteriovenous malformation (AVM) with remarkably dilated vessels resembling an aneurysm. Feeding arteries for this AVM originated from the right internal iliac artery, right lumbar artery and right renal artery, and drainage blood flowed into the inferior vena cava from the dilated vessel via a large vein. At operation the right internal iliac artery and right lumbar artery were ligated and the dilated vessel with AVM, which connected with the right renal artery, was resected. An angiography 16 days after the operation revealed the normal arteries without AVM and the right internaal iliac artery filled through collateral arteries. Recently catheter embolization in frequently the first choice for treatment of AVM. However, in the case of AVM with aneurysmal dilated vessels, surgical resection should be selected.