Ninety-three patients treated by radical irradiation for stage A2, B and C1 carcinoma of the prostate between 1979 and 1988 at a joint radiotherapy service were reviewed. The average age was 63 years, 84% of the patients were white and on histological examination the tumours were well or moderately differentiated in 88% of cases. Treatment was with 5 fractions per week in 71% while the remainder received 3-4 fractions per week. At a median follow-up of 62 months, the 5-year survival rate was 83% and the relapse-free rate was 73% (life table). The most important prognostic factor was tumour grade. In patients with grade 1 and 2 tumours, the 5-year survival rate and relapse-free rate was 91% and 76% respectively, while the survival for grade 3 tumour was 60% and 22% respectively (P less than 0.05 logrank). There was a suggestion that patients diagnosed by trans-rectal needle biopsy did better than those diagnosed by trans-urethral resection, but this was not statistically significant. Disease stage did not influence survival. The crude late complication rate was 10% but this was significantly related to the use of less than 5 fractions of radiation per week. A separate group of 13 patients with local disease who had had failed previous hormonal treatment were not analysed. Their 5-year survival rate was 19%, which is statistically significantly worse (P less than 0.001 logrank).