The authors report 13 cases of ureteral or periureteral sclerosis in a series of 330 cases of renal transplantation (3.9%): they occurred early, were asymptomatic (except for anuria); the renal cavities were always dilated, the renal function always deteriorated; the treatment was essentially surgical without mortality and with a low complication rate but 23% of the transplants were lost because of urological complications at 18 months. The authors compare their series with the literature.