Myelodysplastic syndromes (MDS) are a myeloid neoplasm characterized by abnormal differentiation, ineffective hematopoiesis, and genetic instability with enhanced risk of transforming to acute myeloid leukemia (AML). The diagnosis of MDS is principally made based on the percentage of blasts in the bone marrow and peripheral blood, type and degree of dysplasia and the presence of ring sideroblasts. Recently, for making an accurate diagnosis of MDS, the aberrant antigen expression detection of hematopoietic cells by flow cytometry has been reported to be a useful. However, the diagnostic systems utilized in those studies are rather complicated. We modified an existing flow cytometric scoring system (FCMSS) based on aberrancies in the myeloid lineage and evaluated its usefulness in diagnosing various anemic disorders, including myelodysplastic syndromes (MDS). The flow cytometric score was significantly higher in MDS patients than in those with other anemic disorders, the exception being megaloblastic anemia (i.e., Vitamin B12 deficiency, folate deficiency). The data suggest that our FCMSS may provide useful information for making the diagnosis of MDS and other anemic disorders.