Between 1975 and 1987, 53 patients with radical retropubic prostatectomy for adenocarcinoma of the prostate (pathological stage C or D1) underwent adjuvant radiotherapy. 26 of these patients additionally underwent subcapsular orchiectomy. Radiation therapy was given to 45 patients as 40 to 50 Gy to the pelvic lymph nodes followed by a boost to the tumor bed to a total of 64 to 70 Gy. Only five of the 45 patients received treatment to prostate and pelvis developed progression, whereas four out of eight patients who were irradiated to the prostate alone showed progression (p < 0.01). The five- and ten-year disease-free survival rates of 33 patients with stage C tumors were 91% and 83%, the local control rate 97% and 94%. 20 patients with stage D1 carcinoma showed a five-year disease-free survival of 79% and a local control rate of 95%. 25/26 patients with subcapsular orchiectomy are living disease-free, 8/27 patients without hormonal manipulation had a progression of disease (p < 0.05). All 13 patients with well or moderate differentiated tumor are alive without evidence of disease, 9/40 patients with poor differentiated carcinoma have shown tumor progression (p < 0.05). Compared to published results, our data suggest, that adjuvant radiotherapy can decrease local recurrence and probably increase disease-free survival in stage C and D1 carcinoma of the prostate.