Anomalies of the inferior vena cava and renal veins occur infrequently but if unidentified can lead to significant morbidity during surgical exploration. An understanding of the embryologic development of the vena cava and its tributaries is necessary to understand the genesis of these sometimes complex anomalies and their accompanying anatomic variants. Newer radiologic modalities in the form of spiral computed tomography (CT) and three-dimensional reconstruction of spiral CT allow clear definition of the anatomy of these anomalies. Variations in the embryologic evolution of the vena cava dictate the different venous anomalies that may be encountered in the retroperitoneum. Additionally, the utility of newer radiologic modalities in the identification of these anomalies is discussed.