A 63-year-old woman developed rapidly progressive glomerulonephritis syndrome with serum myeloperoxidase-anti-neutrophil cytoplasmic antibodies (MPO-ANCA). A renal biopsy showed diffuse crescentic glomerulonephritis. Immunofluorescence and electron microscopic studies showed no significant deposits in the glomeruli. The morphological findings were consistent with pauci-immune type crescentic glomerulonephritis. In addition, the patient had erythropoietin-resistant anemia and subsequent pancytopenia. Bone marrow was normocellular without an excess of blasts. However, multinuclear erythroblasts, hypersegmented neutrophils, and megakaryocytes without platelet formation were observed. Chromosome analysis of the bone marrow showed 47,XX,+7. This is the first case of MPO-ANCA-related crescentic glomerulonephritis in a patient with myelodysplastic syndromes (MDS). A possible relationship between MPO-ANCA and MDS is discussed.