Patients with intermediate or high-grade non-Hodgkin's lymphoma are rarely cured of their disease after the failure of conventional therapy. Autologous bone marrow transplantation (ABMT) offers such patients a new possibility of cure. Our purpose was to evaluate the usefulness of radiotherapy. In these patients who did not achieve complete remission of disease after high-dose chemotherapy (HDCT) followed by ABMT or who had previous bulky disease. In this study we examined 10 patients: after HDCT+ABMT, 9 patients had persistent disease and 1 patient with previous bulky disease was in complete remission. All patients underwent involved-field radiotherapy administered by a 6-18 MV linear accelerator, total mean dose 4000 cGy (range, 3200-5000 cGy). At the end of radiotherapy we observed 6 complete responses and 4 progressions of disease outside the radiotherapy field. No serious side effects were observed. To date, of the 6 complete responses 2 have relapsed (after 9 and 11 months) and 4 are alive and disease free at 24 months (range, 8-39 months) after radiotherapy. In our opinion, radiotherapy is an effective treatment after HDCT+ABMT and may have a role in a prospective multidisciplinary approach.