Between 1981 and 1986, we treated 179 newly diagnosed patients with advanced-stage malignant lymphoma or related conditions with methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, bleomycin (MACOP-B). Experience with 12 different histologic subtypes indicates that MACOP-B is acceptably tolerated and effective for diffuse large cleaved cell, diffuse large noncleaved cell, diffuse mixed large and small cleaved cell, immunoblastic, and discordant lymphomas but not for angioimmunoblastic lymphadenopathy or for diffuse small cleaved cell, follicular large cell, follicular mixed large and small cleaved cell, acquired immune deficiency syndrome (AIDS)-related, unclassifiable, or small noncleaved cell lymphomas. Pooled long-term results for the 126 patients with variants of diffuse large cell lymphoma (cleaved, noncleaved, immunoblastic, and mixed) show an actuarial relapse-free survival of 67% for the 86% of patients who had a complete response and an overall survival for all patients of 65% at 78 months of follow-up. Analysis of toxicity reveals a substantially higher risk of lethal toxicity in patients over 59 years of age. MACOP-B should only be used for patients with one of the diagnoses for which it is effective; meticulous care should be taken to prevent severe toxicity in older patients.