The authors report seven cases of abdominal aortic aneurysm rupturing into the inferior vena cava system. Symptoms were protean, but included local clinical manifestations and general findings due to the high-flow arteriovenous fistula. In spite of different types of clinical presentation, the correct preoperative diagnosis was made when a continuous bruit with systolic accentuation was heard over the abdomen. Venous repair consisted of simple closure of the fistula from within the aneurysm in six cases. In one case, treatment required ligation of the right common iliac vein. There were two cases of paraplegia, one before and one after the operation. Two of the seven patients died.