Spontaneous aortocaval fistula is a rare complication of abdominal aortic aneurysm rupture. A definitive preoperative diagnosis sometimes is difficult, because ofnonspecific and highly variable clinical symptoms. Classic signs such as low back pain, palpable pulsatile abdominal mass, abdominal bruit and thrill, dyspnea and high-output cardiac failure are present in less than 50% of cases. In this article we report the case of a 68-year-old patient with an aortocaval fistula who was admitted in hospital because of abdominal pain and hematuria.