Anomalies of the left renal vein (retroaortic left renal vein and left renal vein collar) and the inferior vena cava (left-sided inferior vena cava and caval duplication) occur relatively infrequently but pose potential hazards to the surgeon during aortic repair. We report the cases of three patients in which one or a combination of these anomalies of the renal vein and inferior vena cava was present. The embryologic origins of each of the anomalies are discussed, and suggestions, both surgical and nonsurgical, are proposed that might aid the surgeon in avoiding injury and subsequent bleeding from these anomalous structures during surgical operations on the abdominal aorta.