A 59-year-old woman was admitted in February 1991, because of abdominal distension. On admission, she had splenomegaly, autoimmune hemolytic anemia, and idiopathic thrombocytopenic purpura. Evans syndrome had been diagnosed and daily prednisolone therapy had been performed. After this therapy, a rapid increase of lymphocytes was observed accompanied with contraction of spleen. The monoclonal proliferation of B-lymphocytes and rearrangement of JH and J kappa gene were detected and chronic lymphocytic leukemia was diagnosed. With reduction of prednisolone, the lymphocyte counts decreased and the size of the spleen returned to the previous state. It is suspected that the cause of rapid lymphocytosis in this case was due to the redistribution of lymphocytes from the spleen to the peripheral blood.