Between 1963 and 1977, 941 patients with carcinoma of the breast received, at the University of Texas M.D. Anderson Cancer Center, peripheral lymphatic irradiation alone or with chest wall irradiation after a radical or modified radical mastectomy. None of the patients received adjuvant chemotherapy. The incidence of patients with histologically involved axillary nodes was 70%. The lymphatics of the apex of the axilla, of the supraclavicular area, and of the internal mammary chain were irradiated in patients with histologically positive axillary nodes and/or in patients with central or inner quadrant primaries regardless of the axillary status. When in 1963 an electron beam became available, chest wall irradiation has been added to the peripheral lymphatics irradiation, primarily when there was a heavy infestation of the axillary nodes. The disease-free survival curves tend to flatten out at 10 years. At 10 and 20 years, the disease-free survival rates are respectively 55% and 50% for all patients, 44% and 40% for all patients with positive nodes, 56% and 48% for the patients with one to three positive nodes, and 33% and 30% for the patients with four or more positive nodes. The comparison of the mortality curves between the general population and the breast cancer patients seems to indicate a cured fraction, since the curves become parallel at 17 years. The highest incidence of failures is between 0 and 5 years, still a significant incidence between 5 and 10 years, but after 10 years the incidence of failures is relatively small.