The diagnosis of myelodysplastic syndromes is based on the presence of cytopenias, dysplastic morphological features on peripheral blood (PB) and bone marrow (BM), cytogenetic abnormalities and requires to rule out other diseases resembling these conditions. Optical cytomorphology is the cornerstone of diagnosis of MDS. The recognition of cytological myelodysplasia has a crucial value in diagnosis and prognosis of MDS. Assessment of cytological morphology requires, like other diagnostic techniques (flow cytometry, cytogenetics, histological morphology), experienced observers and the availability of high quality and properly stained samples. The morphological analysis has shown moderate reproducibility among hematopathologists. The better characterization and standardization of morphological features has improved the reliability and reproducibility of MDS diagnosis. Maintaining the competence in morphology assessment requires experience and continuous training. For the correct assessment of cytologic myelodysplasia it is essential to keep in mind the morphology of normal myelopoiesis. To the extent of our knowledge there are no studies describing together morphological data on normal and dysplastic myelopoiesis in the framework of MDS. Therefore, by combining these data, this manuscript could serve as a useful tool for quotidian process of diagnosis.