Two patients with aortic abdominal aneurysms in association with horseshoe kidney are presented, making a total of 34 cases recorded in the literature. In 29 patients, the aneurysm was resected and five patients were non-resectable. Because of the abnormalities in vascular supply to the abnormal kidney, it is important to diagnose the combination of aneurysm and horseshoe kidney preoperatively. An error in diagnosis should be unusual if an intravenous pyelogram is routinely obtained on all patients. This study may reveal abnormalities which will allow the diagnosis of horseshoe kidney to be made or suspected. If the intravenous pyelogram is abnormal, it should be followed by an aortogram. This may substantiate the diagnosis of aneurysm and horseshoe kidney and provide the necessary detailed information regarding the pattern of blood supply and its relationship to functioning tissue. The amount and disposition of functioning renal parenchyma may be further amplified by renal scan. If this sequence is followed, the unanticipated combination of abdominal aneurysm and horseshoe kidney should be rare.