Purpose: To update the results of external radiotherapy with a focal concomitant boost technique on local control and bladder function in patients with muscle-invasive bladder cancer. Patients and Methods: The authors retrospectively evaluated 92 elderly or disabled patients with localized T2-4 N0-1 M0 transitional cell carcinoma of the bladder and a median age of 79 years, not suitable for radical surgery and treated between 1994 and 2005. Treatment consisted of a dose of 40 Gy/2 Gy to the small pelvis with a daily concomitant boost of 0.75 Gy to the tumor. Total dose was 55 Gy in 4 weeks. Results: Complete remission rate after evaluation by means of cystoscopy at 3 months was 78%. 3-year local control rate amounted to 56%, and 3-year overall survival to 36%. The posttreatment bladder capacity was comparable with the pretreatment capacity and was ≥ 200 ml in 81% of the cases. Mean bladder capacity did not deteriorate at longer follow-up. Conclusion: The local control rate after external beam radiotherapy in elderly patients with a focal concomitant boost for localized muscle-invasive bladder cancer was 56% at 3 years. Functional bladder outcome was good. © 2008 Urban & Vogel.