Forty patients with inoperable or not radically resected tumours in the rectum or rectosigmoideum were treated with irradiation combined with 5-fluorouracil, methotrexate and cyclophosphamide. The acute toxicity was moderate, but 3 patients developed late complications such as fibrosis and fistulation in the irradiated area. Twenty-one patients had a measurable tumour within the radiation fields and were included in the evaluation of the tumour response. Of these patients 8 achieved complete and 5 partial tumour remission. Nevertheless, it is emphasized that this treatment cannot be recommended because of severe complications observed in a following randomized series of patients receiving irradiation combined with 5-fluorouracil and methotrexate.