Urethral valves are the commonest congenital infravesical obstruction and, because they are confined to the prostatic canal, render the condition a male disease. Morphologically these valves may be mucosal ridges, folds, cusps or diaphragms. They are most often attached to the verumontanum and, when so involved, this organ is usually otherwise anomalous. When, by location or size, valves produce symptoms, the primary clinical manifestations are those of obstruction; secondary symptoms are those of uremia. The correct diagnosis is easily made by cysto-urethroscopy. Removal of the obstruction constitutes the treatment. The prognosis is directly proportional to the renal function. A study of eighteen cases of congenital posterior urethral valve obstruction is herewith presented; that all of these patients were children lends particular interest to this lesion.1 Although Langenbeck2is generally accredited with the original description 128 years ago (1802), Young3in 1913 was the first surgically to treat