The posterior urethral valves (PUV) realized a low urinary obstruction associated with the persistence of a mucosal fold under the veru montanum. It is the first cause of subvesical obstacle of the child. It is also the most serious obstructive uropathy [1], with a significant risk of renal failure (25 to 40% of cases), sometimes requiring kidney transplantation (1% of children waiting for kidney transplants had PUV). This malformation, which appears very early in the development of the urinary tract, is often isolated. Its cause remains unknown. Antenatal diagnosis is possible in some cases and improves decision in postnatal load.