To determine the long-term treatment outcome and late effects of mantle irradiation alone in selected patients with early-stage Hodgkin's disease. Between 1988 and 2000, 87 patients with pathologic stage (Ann Arbor) I-IIA or clinical stage IA Hodgkin's disease were entered on to a prospective trial of mantle irradiation alone. Patients with B symptoms, large mediastinal adenopathy, or subcarinal or hilar involvement were excluded. The median doses to the mantle field and mediastinum were 36 Gy (range 30.3-40) and 38.6 Gy (range 30.6-44), respectively. The actuarial freedom from treatment failure (FFTF) and overall survival (OS) rates were calculated using the Kaplan-Meier technique. The median follow-up was 107 months (range 23-192). Thirteen of 87 patients (15%) relapsed at a median of 30 months (range 5-62). The 5- and 10-year actuarial FFTF rates were 86% and 84.7%, respectively. All 13 patients who relapsed are alive without evidence of disease at a median of 84 months (range 30-156) post-salvage therapy. Five patients developed a second malignancy at a median of 93 months (range 27-131). The 10-year actuarial risk of a second malignancy was 4.5%. There have been two deaths to date, both due to second malignancies. The 10-year OS rate was 98.2%. In selected patients with early-stage Hodgkin's disease, mantle irradiation alone has an excellent long-term survival rate, comparing favorably with the previous standard treatment of extended-field radiation therapy and the current standard of combined modality therapy.