Bone marrow aspirates of 19 patients with low-risk myelodysplastic syndromes (MDS) and 14 control subjects were collected in order to assess the level of oxidative DNA damage. Glycophorin A positive and negative cells separated by miniMACS magnetic cell sorting were subjected to single cell gel electrophoresis (comet assay) combined with enzymes of base excision repair (endonuclease III and formamido-pyrimidine-glycosylase) that specifically recognize oxidized nucleotides. Compared to controls, MDS patients exhibited a significant increase of oxidative damage to DNA which could contribute to genomic instability and disease progression.