Paraplegia, ischemia of the colon, and gluteal necrosis are uncommon but devastating sequelae of surgery of the infrarenal aorta. These complications are ischemic in nature, secondary to the following technical maneuvers, individually or in combination: bilateral occlusion of the hypogastric arteries; division of a patent inferior mesenteric artery; or proximal end-to-end aortic to common femoral artery bypass grafting accompanied by stenosis of the external iliac arteries. The etiology of paraplegia after infrarenal aortic surgery is of particular interest since it now appears that it is more likely due to interruption of flow to lumbosacral branches of the hypogastric arteries supplying the conus of the spinal cord and/or to division of a low-lying ‘conus medullaris artery’ rather than to occlusion of the higher-lying great radicularis artery of Adamkiewicz. Knowledge of the pelvic circulation to the colon, buttocks, and terminal spinal cord allows the surgeon prophylactically to avoid or reconstruct critical branches during operations on the infrarenal aorta. While rare, severe complications cannot be completely eliminated; hopefully their incidence can be reduced by an understanding of their etiology.