Six cases of aorto-enteric fistulas are discussed. In three patients the aorta ruptured into the duodenum and in three there was rupture into the esophagus. Aorto-enteric fistula is usually caused by atherosclerosis, but may also be due to syphilis or tuberculosis. Following insertion of an aortic graft, fistula is usually the result of breakdown of the anastomosis. Gastrointestinal bleeding usually heralds the problem. The roentgen signs of rupture are pressure on the esophagus or intestine, bleeding into the wall or lumen, and demonstration of the fistula. The abnormal connection may not be demonstrable by aortography. These signs permit early diagnosis and subsequent possible life saving surgical correction.