Radical cystectomy remains the standard treatment for muscle-invasive bladder cancer; however, a substantial number of patients with muscle-invasive bladder cancer are not appropriate candidates to radical cystectomy due to co-morbidities or anxiety regarding bladder preservation. Trimodal bladder-sparing therapy is an intelligent and attractive treatment option for such patients. We established a novel treatment strategy using trimodal treatment with gemcitabine and cisplatin. Patients diagnosed with muscle-invasive bladder cancer by transurethral resection of bladder tumor and who wished for bladder preservation were recruited. The regimens were gemcitabine 300 mg/m2 and cisplatin 30 mg/m2 in day 1 and concomitant irradiation 1.8 Gy/Fr, five fractions per week. Irradiation was administered to the true pelvis up to 36 Gy and was then boosted to the entire bladder until a total of 54 Gy. Transurethral resection of bladder tumor was also performed after chemoradiotherapy to evaluate pathological response to treatment. We evaluated treatment efficacy and survival, safety of chemoradiotherapy with gemcitabine and cisplatin. Thirty-eight patients were enrolled, and three patients were excluded. Pathological complete response after chemoradiotherapy was observed in 31 patients, and the 5-year bladder-intact metastasis-free survival rate was 76%. The 5-year cancer-specific and overall survival rates for chemoradiotherapy were 85 and 75%, respectively, which were not significantly different from those for radical cystectomy (73 and 71%, respectively). Grade 3/4 adverse events included neutropenia (63%), anemia (18%) and thrombocytopenia (37%); however, treatment-related deaths were not observed. Chemoradiotherapy using gemcitabine and cisplatin for muscle-invasive bladder cancer is effective for local cancer control and shows no significant difference in oncological prognosis compared with radical cystectomy.