Between 1974 and 1977, the Cancer and Leukemia Group B (CALGB) initiated four studies which address current major questions in the therapy for Hodgkin's disease. The efficacy of chemotherapy alone as compared with combined modality therapy in patients with poor-prognostic stages I and II is evaluated in CALGB 7751. Currently, both therapies produce very high complete remission rates in asymptomatic patients; the remission rate is better with combined modality therapy in symptomatic patients. Single and combined modality therapies are compared for stage III patients in CALGB 7451. Complete remission rates have been similar, but relapse-free survival is superior for patients treated with local nodal radiotherapy followed by chemotherapy (P = 0.04). In particular, stage IIIA patients with nodular sclerosis seem to benefit from the inclusion of radiotherapy in their initial treatment. In CALGB 7551, the efficacy of chemotherapy alone versus chemotherapy plus radiotherapy to areas of bulky disease is under study in patients with stages IIIB and IV. Currently, a relapse rate of less than 10% has been seen among sites irradiated, and survival is best for patients treated with radiotherapy bracketed by chemotherapy. Finally, the role of two alternating non-cross-resistant combination chemotherapy programs is being studied in CALGB 7552. Relapse-free and overall survival is better with the doxorubicin-containing regimen than with either the alternating or alternate chemotherapy program. At present, the median followup for each of these studies is less than 5 years. Further observation is required to answer the critical questions relating to prolonged disease-free survival and cure.