Portal vein gas as a result of bowel necrosis following occlusion of the superior mesenteric artery has an extremely grave prognosis. Only two previous cases have been recorded as having survived. In both those cases the diagnosis of portal vein gas was made on an abdominal radiograph. The present report is of the first such case surviving after ultrasonic demonstration of portal gas. In this case, no evidence of portal gas was seen on the abdominal radiograph. The increased sensitivity of ultrasound over plain radiography mandates urgent liver and portal ultrasound in all cases of suspected mesenteric event.