Forty-seven adults with advanced malignant lymphoma (the majority in stage IV) were treated with a combination of cyclophosphamide, hydroxyldaunorubicin (Adriamycin), vincristine (Oncovin), prednisone, and bleomycin (CHOP-Bleo). The complete remission (CR) rate was 66%. The overall response (complete + partial remission) was 92%. The CR rate in patients with diffuse histiocytic lymphoma (DHL) was 69%. Only 3 of the 18 patients with DHL in CR have relapsed; the projected median duration of response was calculated to be greater than 2 yr. In patients with nodular poorly differentiated lymphocytic lymphoma (NPDL), the CR rate was 62%. One of the eight patients with NPDL in CR has relapsed; the projected median duration of complete response will be greater than 4 yr. The median survival for all patients entered in this study has not been reached; however, it was estimated that it will be greater than 3 yr. The survival curves became flat at 70 wk for the patients with DHL and at 1 yr for the patients with NPDL. Major complications during chemotherapy with CHOP-Bleo were myelosuppression and alopecia. Only six severe infections occurred during myelosuppression. No hemorrhagic problems were observed. This study indicates that combination chemotherapy with these agents is effective in increasing the CR rate and survival in patients with diffuse histiocytic lymphoma. In patients with NPDL, further observation will be needed to assess the effect of this combination on survival.