Myelodysplastic syndrome (MDS) is a hematological disorder due to abnormal maturation and differentiation of stem cells. It is clinically manifested as cytopenia and commonly seen in elderly persons. Some MDS cases are known to show longitudinal hemolysis, which is attributed to various factors. Human parvovirus B19 (B19V) had been found in blood for transfusion and is also capable of infecting immature erythroid cells. In our study, we made a thorough review of six elderly MDS cases with slight immunological abnormality and longitudinal hemolysis to elucidate their association with B19V infection. Five of the six cases had received blood transfusion prior to coming to the hematological section of our hospital. All the 6 cases were positive for anti-B19V IgG antibody in their sera. In the bone marrow of all the cases, macrophages were observed to be directly in contact with the erythroid islands showing hypocellular marrow by biopsy. Based on the data of these cases, we proposed that hemolysis in elderly MDS patient with immunological abnormality might be related to B19V infection.