PurposeIn pediatric bladder/prostate-rhabdomyosarcoma, the rate of bladder preservation after neoadjuvant chemotherapy is high, with an excellent oncological outcome. Information about functional urological long-term outcomes is rare.MethodsData of all patients who had undergone bladder-preserving surgery with or without brachytherapy at our institution between 2009 and 2020 were analyzed retrospectively. Detailed urological function was assessed focusing on age-related continence, bladder capacity and urodynamic findings.ResultsWe identified 40 patients, median age at surgery of 27 months (range 9–191), and 32 patients additionally received postoperative high-dose-rate brachytherapy. The median follow-up was 32.5 months (range 6–125). The bladder capacity increased from median 66.7% (21.1–180) of expected bladder capacity related to age 3 months after surgery to 87.4% (58.1–181.8) 9 months after surgery. In the group of aged > 6-year-old, continence was 94% (83% with brachytherapy, 100% without brachytherapy). Erectile function was normal in 92% (90% with brachytherapy, 100% without brachytherapy). Bladder capacity was more than 65% expected bladder capacity related to age in 70% (60% with brachytherapy, 86% without brachytherapy). 65% of all patients need neither anticholinergic drugs nor low-dose antibiotics (63% with brachytherapy, 71% without brachytherapy).ConclusionsBladder preservation with good functional outcome can be achieved in localized bladder/prostate-rhabdomyosarcoma. In selected cases, supportive brachytherapy additionally contributes to an improvement in the oncological outcome with calculable risks for bladder and erectile function. Careful urological aftercare should be a fixed priority after oncological follow-ups.