The radiation therapy treatment experience was reviewed for localized prostate carcinoma at the Joint Center for Radiation Therapy [Massachusetts, USA] from 1968-1978 (N = 229 patients, median follow-up of 5 yr). Actuarial 5 (and 8) yr survival rates for clinical Stage A (N = 25), B (N = 85), and C (N = 88) disease were 96% (82), 77% (63), and 61% (38). The corresponding 5 (and 8) yr relapse-free survivals were 84% (67), 68% (61), and 53% (36). Actuarial rates of clinical local failure at 5 (and 8) yr were 0% (0), 12% (20), and 15% (30) for Stage A, B, and C, respectively. There was a suggestion of a decrease in the force of local and overall recurrence after 8 yr, although further follow-up will be necessary for confirmation. Among 42 patients who underwent pelvic lymphadenectomy followed by irradiation, lymph node status appeared to be a strong predictor of distant failure (9% (3/32) failures for node (-) patients compared to 70% (7/10) for node (+) patients). Twenty-nine patients received radiotherapy after radical prostatectomy for clinically palpable (Stage B and C) tumor. Only one of 16 patients treated post-operatively because of microscopic or gross residual disease has developed recurrence. By contrast, only 2 of 13 patients irradiated because of clinical local tumor recurrence remain alive and free of disease. Radiation therapy can provide effective long-term local control of prostate carcinoma, but that the ultimate radiocurability of the disease is not yet known.