The development of either histiocytic lymphoma or Hodgkin disease in association with pre-existing chronic lymphocytic leukemia has been described in the literature as a terminal event. We describe two patients in whom the diagnosis of a second malignant lymphoma was made during life and who achieved objective clinical response after a change in therapy to a more aggressive combination of drugs. We conclude that patients with chronic lymphocytic leukemia who have had a sudden change in their clinical course should have thorough reevaluation, looking specifically for the development of a second lymphoproliferative disorder. If this is discovered, more aggressive therapy should be initiated.