A 74-year-old man had a right common iliac aneurysm perforating into his inferior vena cava. He showed a pulsating abdominal mass, claudication of the right leg and swelling of both legs. The fistula was preoperatively diagnosed by aortography. The fistula was closed with two interrupted 3-0 monofilament sutures with pledgets within the aneurysm, by clamping all vessels communicating to it. The aneurysm was replaced with a Y-shaped Dacron graft. The postoperative course was uneventful and the patient was discharged on the 17th postoperative day without any leg claudication or swelling of the legs. This complication is rare, with only 7 such reports in Japan. It should be surgically managed as soon as the diagnosis is confirmed. Clamping all vessels communicating to the fistula in closing it is a safe and reliable approach.