Background: Radical cystectomy is still the standard treatment for muscle-invasive bladder cancer (MIBC), while the patients with MIBC are not always appropriate candidates due to multiple comorbidities. We establish novel treatment strategy by trimodal treatment. Methods: The regimen was gemcitabine 300 mg/m², and cisplatin 30mg/m² in day 1 and concomitant irradiation 2Gy/Fr, 5 fraction per week. Irradiation was administered to whole pelvis up to 30Gy, then boost to true pelvis until total 48Gy to 54Gy. Extensive transurethral resection (TURBT) was performed and we confirmed pathological stage ≥T2. TURBT was also performed after chemoradiotherapy to evaluate the pathological response to treatment. This study was approved in our institutional review board (ID: H23-89) and the information was opened on UMIN (ID: UMIN000006363). We analyzed their treatment efficacy and survival. Results: The patients were 29 men and 9 women, median age was 76.5 y.o. and median follow up was 23 months (1 - 112). Clinical stage T2, T3, T4, N1 and N2 were 23, 10, 5, 4, 2 cases, respectively. The 2- and 5-year metastatic-free survival (MFS), bladder-recurrence free survival (bRFS), cancer-specific survival (CSS), and overall survival (OS) rates after treatment were 91.7 and 84.0%, 59.7 and 42.6%, 87.3 and 87.3%, and 87.3 and 81.8%, respectively. Salvage cystectomy was performed 3 patients and they were still alive. CR rate was 78.9% and overall response rate was 92.1%. cT stage and valiant histology was not associated with treatment response. The patients achieved CR had significant good prognosis in CSS (p=0.0149) and OS (p=0.0149) compared with non-responders. In cox hazard model, CR achievement was significant prognostic factors for OS (p =0.0015, HR 6.804e+26, 95% CI 56.94-1.631e+86). Patients were able to receive 3 to 5 cycle GC radiation and any grade 3 or more adverse event was 7 (18.4%) cases. no treatment related death was recorded. Conclusions: In selected patients, GC radiation for MIBC may provide good oncological outcomes as bladder preservation strategy.