The retrocave ureter is a rare congenital malformation of the right ureter which describes in its lumbar portion a loop with anterior concavity passing behind the inferior vena cava.It is an anomaly related to a defect in the development of the inferior vena cava whose clinical translation, when present, is related to a degree of ureteral obstruction and its complications. It is necessary to make the diagnosis of retrocavity ureter to avoid its complications and for a better therapeutic management.The diagnosis of patent forms threatens the renal prognosis; the management must be early because a simple ureteral plasty can usually save the kidney.