Synovial vascularization in metacarpophalangeal joints of a patient with rheumatoid arthritis treated with leukocytapheresis (LCAP) was evaluated by Doppler sonography. After the treatment with LCAP, evaluation with American College of Rheumatology core set showed improvement, and the levels of C-reactive protein and serum amyloid A protein decreased. Power Doppler sonography demonstrated a reduction of color flow signals of the joints, and spectral Doppler sonography demonstrated an increase in vascular resistant, indicating a reduction of vessel's permeability. This is the first report evaluating a synovial vascularization and blood flow of the joints by Doppler sonography before and after LCAP therapy. Doppler sonography might be one of the useful methods for evaluating the therapeutic response of LCAP.