False aneurysm of the infrarenal aorta was found at the site of proximal anastomosis in 13 patients after vascular reconstruction for lower limb arterial disease. The grafts involved were aortoprosthetic in one patient, aortobiiliac in two patients, and aortobifemoral in 10 patients. They had been implanted eight years prior to reoperation on the average (range six months to 15 years). False aneurysm was diagnosed because of abdominal pain in four cases, embolism in two cases, intestinal hemorrhage in one case, and during routine sonographic or computed tomographic (CT) scan surveillance in the six other cases. Femoral false aneurysm was associated in eight of 10 cases with femoral anastomoses. Aortic false aneurysms were repaired by interposition of a prosthetic tube between the infrarenal aorta and the original prosthetic graft in 11 cases and by changing the aortobifemoral graft in two cases. In one further case, repair was accomplished by implanting an aortobifemoral prosthetic graft laterally on a prosthetic tube interposed between the infrarenal aorta and the body of the original prosthetic graft, which continued to irrigate the internal iliac arteries. There was no mortality. Thrombosis of a prosthetic branch occurred in one case and was treated by thrombectomy. One patient underwent reoperation for intestinal obstruction. Two others had distal embolism responsible for toe necrosis. Anastomotic false aneurysms should be looked for routinely during the surveillance of prosthetic grafts implanted on the infrarenal aorta, especially when femoral false aneurysm is found. Preservation of pelvic vascularization must be an integral part of management.