From 1979 through April, 1985, 74 patients were treated by percutaneous irradiation for local recurrences of colorectal carcinomas. The treatment consisted of a contralateral irradiation up to a dose of 40 Gy and a small-volume boost up to 60 to 66 Gy. In case of progressive remote metastases, the treatment was finished at 50 Gy. 53 patients received a dose of 50 Gy or more and were followed for at least six months. The decisive prognostic parameter was the presence of remote metastases when the recurrence appeared (n = 32). The median survival was six months, in patients without remote metastases at this moment it was 15 months. A complete or considerable relief of pain was obtained in 78%; it continued for a median period of 8.5 months, although most of the patients showed a new local tumor progression after an interval of three to 26 months. Computed tomography showed only small regressions or, in most cases, unchanged volumes of the tumors.