Recently, organ-preserving regimens using predominantly multiple-modality therapy, consisting of endoscopic transurethral resection followed by irradiation with concurrent chemotherapy, are emerging as viable alternatives for muscle-invasive bladder cancer, although radical cystectomy has been the standard treatment. Three cases with muscle-invasive bladder cancer (5-7 cm in size), two of T2N1M0 and one of T2N0M0, underwent bladder preservation therapy with regional hyperthermia for improvement of the local effect. A total dose of 66-70Gy in the conventional methods, chemotherapy composed of methotrexate, doxorubicin, cisplatin and/or vinblastine, and 3 to 12 sessions of hyperthermia during radiotherapy were delivered. All three cases showed complete response without any local recurrence or distant metastasis in follow-ups. Toxicity during the treatment was acceptable, and late toxicity was not recognized. Bladder preservation therapy adding regional hyperthermia is potentially useful for improving the treatment results for muscle-invasive bladder cancer of large tumor size.