Aortic surgery in the presence of horseshoe or ectopic kidneys requires careful planning. A preoperative CT scan is the best noninvasive study, because it permits both delineation of the aorta and identification of the renal anomaly. Preoperative arteriography is essential to define the frequently multiple and anomalous renal arteries. In the presence of a "pancake" kidney, "hostile" abdomen, infrarenal aortic aneurysm without iliac involvement or thoracoabdominal aneurysm, the retroperitoneal approach has clear advantages. If the transperitoneal approach is used, the horseshoe kidney should be mobilized anteriorly off the aorta, and the graft placed posterior to the kidney. Division of the isthmus should be avoided, if possible. A careful search for accessory renal arteries should be undertaken, keeping in mind that arteriography may miss some arteries. Ligation of accessory renal arteries should be avoided, because this may lead to renal necrosis. Standard renal preservation techniques should be used, including mannitol and furosemide infusion before aortic cross-clamping, and cold balanced salt solution perfusion of the renal artery orifices. In most instances, accessory renal arteries can be reimplanted using the Carrel patch technique. In patients with pelvic kidney, cold renal perfusion and topical cooling of the kidney with ice slush should provide satisfactory protection. Perioperative morbidity seems to be increased, although the chances of survival after elective aortic reconstructions are excellent.