Many investigators have regarded Stage III lymphomas as a generalized form of disease and have accordingly recommended systemic treatment programs. Between 1961 and 1973, 68 patients with clinical or pathologic Stage III non-Hodgkin's lymphomas were seen in the Division of Radiation Therapy at Stanford University Medical Center and were treated by high dose (3500 rads or more) total lymphoid radiation therapy only. Of the 17 patients who had a diffuse histologic pattern, the actuarial survival at 5 years was 39%, but only three patients have remained free of disease. In contrast, for the 51 patients who had a nodular histologic pattern, the actuarial survivals at 5 and 10 years were 75% and 65%, respectively. Corresponding relapse-free survivals for patients with nodular lymphomas were 43% and 33%, respectively. Of 28 patients who relapsed with nodular lymphomas, 18 (64%) had relapses confined to lymph nodes; six of these were extensions to previously unirradiated epitrochlear-brachial nodes. Seven of the 18 patients were treated only with further conventional external radiation therapy at the time of their relapses and remain free of disease for additional periods of 2 to 5 years. Hence, 30 of 51 (59%) patients with nodular lymphomas have thus far been controlled by high dose total lymphoid irradiation only. Over 90% of relapses among patients with nodular lymphomas were seen within the first 5 years. The data suggest that high dose conventional radiation therapy to incorporate not only the routine total lymphoid fields but also the epitrochlear, mesenteric, and Waldeyer's ring region has curative potential even in Stage III non-Hodgkin's lymphomas, especially in the nodular group.