Three years ago the patient was pointed out splenomegaly and leukocytosis associated with no swelling of lymphatic glands after pneumonia, but had no complains till admission's time. Leukocytosis was always counted over 10000, and was occupied indifinite large lymphcytes identified as Downey Ⅱ type cell at 55.6% in maximum of its classification. Bone marrow, red blood cell, reticulocyte and platelets count were normal. Spleenbiopsy showed a full of atypical lymphcytes without leucaemic infiltration in spleen. The infiltration of same atypical lymphcytes with intensely degenerated nature were found by liverbiopsy, and these cells had not any tendency to increase in the liver. Axillary lymphatic gland extirpasion's tissue picture coincided with chronic lymphadenitis, and extensive reticulo-and sinusendotheliar cell increasing were also seen. Several serologic reactions, i.e. Paul-Bunnel reation, Weil-Felix reaction and Davidson's adosorption test had little value to making diagnosis.