We report the incidence of urological complications in a series of 1,200 kidney transplant: 3.8 percent of the patients developed a urinary fistula, due to ureteral necrosis in 48 percent of cases, and 6.5 percent had urinary obstruction. Urinary fistulas are early complications appearing 20 days after the transplantation, while obstructions appear about one year after grafting. These complications are now usually treated by percutaneous and/or endoscopic techniques.