Aneurysmal rupture into the intestinal tract is a rare but disastrous complication of an internal iliac artery aneurysm. We report herein the successful surgical repair of a fistula between a huge aneurysm of the right internal iliac artery and the rectum in an 81-year-old man. After a femoro-femoral cross-over bypass had been performed, the aneurysm was opened and its patent arterial branches were ligated with sutures. The fistula was then intra-aneurysmally sutured and covered with an omental flap. The diagnostic and therapeutic approaches to this severe complication are discussed with a review of the literature following the presentation of this case.