Felty's syndrome is a variant of rheumatoid arthritis with a triad of leukopenia, splenomegaly and typical rheumatoid arthritis, and often accompanies the other extraarticular symptoms, such as subcutaneous nodules, lymphadenopathy, anemia, thrombocytopenia, leg ulcers, fever and weight loss. In addition to the decreased number of leukocyte, impaired functions of leukocytes were also revealed. These changes were considered as the cause of repeated infections, which was the major cause of death in Felty's syndrome. Splenectomy is not fully effective for leukopenia and for the repeated infection. Glucocorticoid therapy can increase leukocyte count, at least tentatively. It has been reported that gold was effective for leukopenia, repeated infection and skin ulcer. However, the definitive way of treatment of this syndrome based on the pathogenesis of this syndrome, remains to be established.