A 10-year-old girl presented with massive pericardial/pleural effusion with anasarca 216 days after an allogeneic bone marrow transplantation from her HLA-matched sibling for relapsed acute lymphoblastic leukemia. She did not show any other symptoms of chronic graft-versus-host disease (GVHD). The antinucleolar antibody was elevated in the blood and the pleural fluid. The lymphocytes in the fluid were mostly CD8+/HLA-DR+, and a majority of CD8+ cells in the blood expressed CD57. These data suggested that she had chronic GVHD. Immunosuppressive therapy including prednisolone, cyclosporin A, high-dose methylprednisolone, tacrolimus (FK506), and methotrexate had no effect, and the patient died of Aspergillus pneumonia 183 days after the presentation of the disease. Although it has not been described before, isolated serositis with edema should be recognized as a clinical feature of chronic GVHD.