A 54-year-old Japanese woman was diagnosed with rheumatoid arthritis (RA) in 1995 on the basis of symmetric effusive polyarthritis, morning stiffness, and strongly positive rheumatoid factor. She had received low-dose prednisolone, indomethacin, methotrexate (MTX), and cyclophosphamide (CPA), at least, over 4 years before the current admission and showed partial improvement of polyarthralgia. In November 2002, she suddenly developed thrombocytopenia (platelet count was 0.3 x 10(4) mm(-3)) with purpura and was diagnosed with immune thrombocytopenic purpura (ITP). As she had refractory ITP, the administration of pulsed high-dose dexamethasone (DEX) therapy was started, resulting in the complete remission of ITP. The present paper reports that pulsed high-dose DEX therapy was useful for the treatment of refractory ITP associated with RA.