Fistula between arteries and the gastrointestinal tract are a rare cause of gastrointestinal bleeding, but potentially fatal. The recognition and early treatment can modify the patient prognosis. We report a case of a patient with previous surgery for seminoma of cryptorchidic testicle, with massive lower gastrointestinal bleeding. We performed the diagnosis and surgical treatment of the fistula between left external iliac artery and sigmoid colon. The patient was successfully treated by external iliac artery ligation and left colectomy.