The alarming diagnosis of leukemia is apt to result in profound emotional disturbances in the patient and his family. The serious implications of leukemia in general frequently overshadow the relatively benign nature of many cases of chronic lymphocytic leukemia. This occasionally leads to vigorous treatment wherein the risks of profound marrow depletion may not be properly weighed against the objectives of therapy. Also, chronic lymphocytic leukemia, occurring as it does in the elderly, is frequently erroneously implicated as responsible for symptoms of other degenerative and neoplastic diseases which happen to be independently present in the same patient. For these reasons, knowledge of the natural course of the disease is necessary as prerequisite for its intelligent management. Previous studies suggest a prolonged course in chronic lymphocytic leukemia,1-5but there are few reports relative to the rate of progression of symptoms and signs in these patients. The occasional appearance of case