In order to develop a low toxicity regimen of bladder radiotherapy for the palliation of patients with poor performance status we carried out a Phase II study of weekly 6 Gy fractions to a maximum dose of 30-36 Gy in 65 patients with T(2)-T(4) bladder cancer (median age 81 years). A complete response was obtained in 23/37 (62%) assessable patients at cystoscopy. Local control was achieved in 16/65 (25%) patients. The median survival of all 65 patients was 35 weeks, and the 2-year actuarial survival 21%. The main acute toxicity was urinary frequency as often as hourly at the peak of the reaction (Radiation Therapy Oncology Group (RTOG) grade 3) in seven patients, and urinary obstruction (RTOG grade 4) in one. The reactions may have been compounded by the effects of locally advanced tumour. Late bladder toxicity amongst the 16 patients who were evaluable after 1 year included four patients with persisting frequency, one with severe haematuria (RTOG grade), and one with a bladder capacity <100 ml (RTOG grade 4). One patient experienced RTOG grade 4 late bowel and bladder morbidity. Weekly 6 Gy fractions to a total dose of 30-36 Gy is a satisfactory palliative regimen for patients with advanced bladder cancer who cannot tolerate standard radical radiotherapy, but it may produce significant late bladder morbidity.