In the last 110 cases of genital prolapse examined, IVU formed part of the prior urological investigation. 14 cases of ureteropelvic distension were thus discovered (13.6% of cases). In ten cases the prolapse was sufficiently largee as to exterioris the uterus or bring it to of the vulva. In 13 cases out of 15 a larg cystocoele was visible at the vulva with a full bladder. The precise urological consequences of these prolapses was greater than had been expected: 13 cases of incomplete vesical retention, 4 of unilateral ureteropelvic distension and 10 bilateral, including 3 only symmetrical. Bilateral high distension was in general associated with a large cystocoele. Severe renal insufficiency was seen in only one case, and 5 moderate elevations in blood urea, in 5 cases. The mechanism of such ureteropelvicalyceal distension is not clear, but the prolapse is directly responsible, since mechanical (insertion of a pessary) or surgical reduction of the prolapse restores the upper excretory tract to normal. Renal function recovered all the more rapidly when the prolapse had been present for a shorter time.