This second part of the 2-part MDS and MPN lecture series covers the diagnosis of myelodysplastic syndromes (MDS), including the criteria required to establish a diagnosis of MDS, challenges in distinguishing MDS from non-neoplastic conditions, and the morphology, clinical features, and genetics of each MDS entity in the 2016 WHO Classification. This lecture is intended for residents during their hematopathology rotation as well as senior residents and hematopathology fellows wishing to review the principles of MDS diagnosis and classification.