A quadruple combination chemotherapy with ACNU, adriamycin, methotrexate and prednisolone (AAAP), was performed on 9 patients with non-Hodgkin's lymphoma, who had been previously treated with a VEPA (P) regimen. Complete remission rate was 44% (4/9) and, in four other patients, the tumor was decreased in size. Complete remission duration was from 30 days to over 390 days. Median survival time was 105 days. Myelosuppressive toxicity was severe. In eight patients, WBC counts were less than 3,000/mm3. In six patients, platelet counts were less than 100,000/mm3. An AAAP regimen is useful in relapse or for resistant forms of non-Hodgkin's lymphoma.