As of January 1986, 13 patients with adenocarcinoma of the prostate had been treated in our clinic by remote after-loading transurethral high dose rate radiotherapy using a 60Co source. Of these patients, four were at stage B2, three at stage C, three at stage D1, and three at stage D2. The mean total dose of transurethral radiotherapy was 35.2 Gy to the most distant prostatic capsule from the source. Three patients with stage D1 disease and one patient with stage C disease received additional external radiation with a total dose of 20 Gy to the prostate and 40 Gy to the pelvis. Local tumor response proved rapid and satisfactory as verified by rectal examination, ultrasonography, and needle biopsy. Serious complications such as proctitis, cystitis, incontinence, and urethral stricture were not evident during the average follow-up term of 34.9 months.