Carcinoma of the bladder (CaB) is a common and important tumor in North America and Western Europe. There has been a steady increase in the incidence of CaB during the past 25 years in both of these regions with a simultaneous decrease in the mortality rates. The decrease in mortality is primarily due to an earlier diagnosis and the availability of more effective therapeutic interventions resulting from major advances in surgery and a wide use of multimodality bladder preservation therapy.The use of radiotherapy in the management of muscle-invasive CaB has undergone a major evolution. External beam radiotherapy alone is used infrequently in carefully selected patients. The same applies to the use of preoperative irradiation. Brachytherapy alone or combined with external beam radiotherapy has been used successfully in Europe but is used infrequently in North America. External beam radiotherapy is an essential component of a multimodality therapy consisting of cytoreductive surgery via transurethral resection of a bladder tumor followed by a planned combination of radiotherapy and chemotherapy. The outcomes of this bladder preservation therapy are similar to those reported in a like patient population treated with radical cystectomy. The main benefit of conservatively treated patients is functioning bladder in about 50% of those receiving conservative therapy. Radiotherapy alone or in a combination with chemotherapy remains an important and effective palliative therapy for patients with recurrent and/or metastatic CaB. Current research efforts are directed toward a better identification of important pretreatment risk factors predicting failure thus helping in a more optimal selection of patients who would benefit most from radical cystectomy or from the application of bladder preservation therapy.