From April 1972 to September 1979, 121 patients with Hodgkin's disease clinical stages IInA, IB, IIB or III successively received MOPP 6 courses in a first trial and 3 courses in a second trial, prior to extended field irradiation; 118 patients underwent surgical restaging prior to irradiation. Anatomical findings demonstrated that 3 courses of MOPP were as effective as 6 courses to treat occult splenic disease. Comparison between clinical and surgical restaging confirmed the reliability of clinical criteria of complete remission after chemotherapy. After extended field irradiation, actuarial survival and relapse-free survival at 4 years were the same whether the patients had received 6 or 3 courses of MOPP.