A 59-year-old man was initially diagnosed as having Hodgkin's disease, nodular sclerosis type, and complete remission was achieved after combination chemotherapy. One year later, he developed a high fever and recurrence of the Hodgkin's disease was diagnosed. Salvage chemotherapy was ineffective, and the patient died. Autopsy specimens showed infiltration of lymphoma cells into multiple organs. Lymph nodes showed characteristics of non-Hodgkin's lymphoma, with expansion of anaplastic large cells; this differed from the histological features at initial diagnosis. Immunohistochemical staining was positive for CD30/Ki-1, but negative for CD15 (LeuM1). These findings were compatible with Ki-1 lymphoma, suggesting that this may be a case of CD30/Ki-1 lymphoma preceded by Hodgkin's disease and that a certain proportion of Ki-1 lymphomas and Hodgkin's disease may share the same cellular origin.