We have evaluated dyshemopoietic features in bone marrow (BM) samples obtained from healthy people aged over 50 without peripheral blood (PB) cytopenia patients and compared them with MDS patients. Control group displayed BM features of dyserythropoiesis and dysgranulopoiesis in up to 15 and 27% of the considered cell elements (P90) respectively, overlapping in part with MDS patients. Interobserver agreement in dyshemopoietic features was highest for BM blast cell and pathological sideroblast counts. An algorithm based on BM blast cell and pathological sideroblast counts that has been verified on 613 patients from different Spanish centers may be of help to improve reproducibility in Myelodysplastic syndrome (MDS) diagnosis.