Purpose: Ureteric substitution using the Yang-Monti principle was reported as a modifi cation of simple ileal ureter replacement. In this study, we evaluate its safety, surgical outcome and impact on renal function. Materials and Methods: Sixteen patients underwent ileal ureter replacement using the Yang-Monti principle to overcome long ureteric defects. Exclusion criteria included patients with elevated serum creatinine > 1.8 mg/dL, infl ammatory bowel syndrome or irradiated bowel. Antirefl ux implantation into the bladder was performed in 12 patients while 4 patients with intact healthy lower ureters underwent distal ileal-ureteral anastomosis. Follow-up protocol was carried out for up to 3 years in 9 patients. Results: No intra-operative or postoperative mortality or signifi cant complications occurred. There were minor complications in the form of urinary leakage that necessitated prolonged ureteric stenting in one patient, superfi cial wound infection in another one and 3 patients developed treatable urinary tract infection without late harmful effects. During follow up, no excess mucus production or metabolic abnormalities were encountered. All patients had preserved renal function (improved in 13 patients and stabilized in 3) without any evidence of urinary obstruction. Conclusions: The reconfi gured ileal segment for ureteric substitution is a safe technique with an excellent outcome. It uses short ileal segments for reconstruction of an ileal tube of adequate length and optimal caliber that permits easy antirefl ux implantation into the bladder so it is not associated with excess mucus production or metabolic abnormalities and offers a durable preservation of renal function without urinary obstruction.