We report Hodgkin's disease arising in a 68-year-old patient with a history of chronic lymphocytic leukemia for 8 years. The patient presented with a 4-month history of weakness, loss of appetite, and a 15-pound weight loss. A bone marrow biopsy showed two distinct histologic types of lymphoma: chronic lymphocytic leukemia and Hodgkin's disease. Immunohistochemical studies showed that chronic lymphocytic leukemia cells were composed of kappa-light chain-restricted monoclonal B cells. The Reed-Sternberg cells expressed CD15. Epstein-Barr virus RNA was not identified in either the Reed-Sternberg cells or cells of chronic lymphocytic leukemia by in situ hybridization. To our knowledge, this is the second reported case of composite Hodgkin's disease and chronic lymphocytic leukemia involving the bone marrow.