We have reviewed the records of 37 patients with pathologically staged IIIA Hodgkin's disease, treated from 1970 to 1982. Twenty patients were staged IIIA1 and 17 staged IIIA2. Treatment consisted of total nodal irradiation in 33 patients (eight of whom received adjuvant MOPP), and mantle plus para-aortic irradiation in four patients (all of whom received adjuvant MOPP). Five-year relapse-free survival (RFS) in patients without splenic involvement was 77% versus 49% for those with splenic involvement (p = 0.43). Five-year RFS in patients treated with irradiation and chemotherapy (RT/CT) was 76% vs. 47% for patients treated with irradiation alone (p = 0.12). RFS was not influenced by sex, mediastinal involvement by tumor, or anatomic substage. Overall survival (corrected for deaths due to intercurrent disease) for the entire group of patients was 92% at 5 years and 87% at 10 years. Sex, mediastinal or splenic involvement by tumor, therapy (RT vs. RT/CT), or anatomic substage did not significantly influence survival. We currently recommend RT/CT only for those patients with extensive splenic involvement and/or Stage IIIA2 disease. We feel that the poor prognosis of these patients justifies the use of RT/CT and its risk of second malignancies.