Objectives: To assess perioperative outcomes, complications, and rate of uretero–ileal anastomotic stricture (UAS) in patients undergoing retrosigmoid ileal conduit after radical cystectomy (RC). Patients and Methods: Clinical records of consecutive patients receiving retrosigmoid ileal conduit after open RC for bladder cancer between March 2016 and June 2020 at two academic centres were prospectively collected. Two expert surgeons performed all cases. Operating room (OR) time, estimated blood loss (EBL), transfusion rate, and 90-day postoperative complications classified according to the Clavien–Dindo system, were assessed. In particular, rate of UAS, defined as upper urinary tract dilatation requiring endourological or surgical management, was evaluated. Results: A total of 97 patients were analysed. The median (interquartile range [IQR]) OR time was 245 (215–290) min, median (IQR) EBL was 350 (300–500) mL, and blood transfusions were given to 15 (15.5%) cases. There were no intraoperative complications. There were 90-day postoperative complications in 33 patients (34%), being major (Grade III–V) in 19 (19.6%). Two patients died from early postoperative complications. At a median (IQR) follow-up of 25 (14–40) months, there was only one case (1%) of UAS, involving the right ureter and requiring an open uretero–ileal re-implantation. Conclusion: The retrosigmoid ileal conduit is a safe and valid option for non-continent urinary diversion after RC, ensuring a very low risk of UAS at an intermediate-term follow-up.