Intrahepatic interruption of the inferior vena cava (IVC) with azygos and hemiazygos continuation is a well known anomaly. An aneurysm of the IVC has to our knowledge never been reported. A patient is described in whom a postrenal segmental aneurysm of the IVC in association with infrahepatic interruption was evaluated by cavography, ultrasound, and computed tomography. The different modes of evaluation are discussed with emphasis on the embryogenesis of the Iv'C.