Radical radiotherapy has been established as an effective modality for eradicating localised prostate cancer. No satisfactory comparisons have been made with patients treated by total prostatectomy, but in surgically staged patients with negative lymph nodes survival after radiotherapy exceeds that of an aged matched population, cancer deaths occurring in only 6-15% of patients and 85% remaining free of local recurrence after 10 years. Results are predictably less satisfactory in surgically unstaged cases and for more advanced localised presentations. Nevertheless, radical radiotherapy achieves local control of disease in the majority of patients. Improved local control may be obtained by increasing radiation dose but at the expense of increased radiation-induced side-effects. Conformal radiotherapy and combined modality treatment with the neoadjuvant or adjuvant androgen deprivation show considerable promise as novel methods to improve the therapeutic ratio, and prospective randomised studies are underway to test these approaches.