Croissed renal ectopia is a very rare congenital anomaly. It designates a transposition of the two kidneys on the same side of the midine with one of the ureters, of length adapted to the seat of the ectopic kidney, which croisses the midiline to implant in the bladder on the opposite side.It is due to an anomaly in the embryonic development of the metanephretic blastema between the fourth and eighth week of management. Renal fusion between the two parenchyma is frequent and this anomaly is most often asymptomatic and discovered by chance.During this anomaly the treatments is linked to the existence of symptoms and/or complications. We report the observation of a 27-year-old patient,mother of two children with a history of two caesarean sections in 2008 and in 2013 for basin limit, presentint with crossed renal ectopia without fusion of the extremities, discovered fortuitously durind an abdomino-pelvic ultrasound for pain in the right flank radiating into the right iliac fossa,collected in the radiology and medical imaging department of University Hospital Center point G, whose purpose of this work was to bring the place of ultrasound in the diagnosis of renal ectopia croissed without fusion with a review ohe literature.