Nine adult patients with Ki-1-positive large-cell anaplastic lymphoma were treated with MACOP-B. Two suffered from relapsed disease and had previously received chemotherapy; a third patient had received a single dose of 100 mg/m2 cisplatin before initiation of MACOP-B. The stage of lymphoma was determined according to the Ann Arbor Conference criteria and was II in one, III in two and IV in six patients. All patients had constitutional symptoms. Five patients had achieved complete remission 4 weeks after termination of the protocol and there were two partial remissions. One patient died of massive pulmonary embolism during the 4th week of treatment; another patient, who had received MACOP-B as salvage therapy, died of progressive lymphoma 1 month after completion of the regimen. Maximal observed toxicities according to WHO were mucositis grade 3 (n = 3) and there were three cases with thromboembolic complications, including a fatal pulmonary embolism in a young patient. However, MACOP-B appears an effective, fairly well-tolerated and feasible therapy for patients with Ki-1-positive large-cell anaplastic lymphoma.