Transcaval ureter is a rare congenital anomaly characterized by an inferior cava vein duplication producing a vascular ring around the right ureter, usually determining hydroureteronephrosis. The knowledge of this vascular anomaly on imaging examinations permits to avoid erroneous diagnosis of retroperitoneal masses or adenopathy and preoperatively advise the surgeon of potential sources of complications. We describe a case of transcaval ureter studied with multidetector computed tomography. To our knowledge, this is the first case in which computed tomography multiplanar and volume-rendering reconstructions show this rare anomaly.