The chief complications of retroperitoneal fibrosis RPF in the ureteric compression ab extrinseco by fibrotic tissue. In the period 1994 to 1999, we treated two cases of idiopathic RPF: the first case a 49 years aged man, presented a left hydronefrosis and bilateral ureteral displacement to the midline. RMN showed widespreads fibrotic tissue in the retroperitoneal space. At operation, the histological findings was that of aspecific fibrositis. The surgical procedure was ureterolysis and lateralization of both ureters with the aid of a wrapping with a pedicled omental graft. The patient was also treated with metilprednisolon, 8 mg-die, for altogether twelve months, Now he is asymptomatic. The second case, a man aged 60, had a compression of both ureter by fibrotic tissue down to the pelvic tract; the histologic picture was the same of that of the first case. A difficult ureterolysis was carried on, plus an omentoplasty and a left ureteral reimplantation to the bladder. Medical treatment followed, following the above scheme. Seven months after surgery the patient is well. This experience of ours urological complications of RPF is confirmatory of the importance of a sound surgical approach and of a tight follow up as well as a sustained corticosteroid therapy in order to prevent relapse.