Between January 1, 1980, and June 30, 1989, 9 patients (6 males and 3 females) developed ischemic injury to the spinal cord or lumbosacral plexus following 3,320 operations on the abdominal aorta (0.3%). The incidence of this complication was 0.1% (2 of 1,901) after elective and 1.4% (3 of 210) after emergency abdominal aortic aneurysm repair, and 0.3% (4 of 1,209) after repair for occlusive disease. Three of the latter had prior clinical evidence of distal embolization. Eight grafts were bifurcated (aorto-iliac:four, aorto-femoral: three, aorto-ilio-femoral:one). One patient underwent extra-anatomic revascularization. Only two patients had supraceliac aortic cross-clamping and one patient underwent exclusion of both internal iliac arteries. Four patients had hypotension. Early mortality was 22% (two of nine). Severe perioperative complications, mostly due to associated visceral and somatic ischemia and sepsis, were present in seven of the nine patients. The extent and type of the neurologic injury correlated with long-term outcome. Patients with ischemic injury of the lumbosacral roots or plexus had better recovery. Attention to the pelvic circulation and the collateral blood supply is important. Use of gentle technique to prevent embolization, avoidance of hypotension and prolonged supraceliac cross-clamping, revascularization of at least one internal iliac artery, and the use of heparin may decrease but not eliminate paraplegia. Once this unexpected complication occurs, careful neurologic evaluation should be done to localize the lesion and aid prognosis.