The myelodysplastic syndromes (MDS) are a heterogeneous collection of bone marrow disorders characterized clinically by cytopenias, a propensity for evolution to acute myeloid leukemia, and for patients to have a significantly truncated survival compared to age-matched controls. MDS are the most common myeloid malignancy, with approximately 15-20,000 new diagnoses yearly in the U.S., and an average age at diagnosis of 70 years. This session will review prognostic scoring systems used in MDS, including their use as default staging systems, the recent incorporation of molecular data into these systems, and how they are applied to make therapeutic decisions. Management of special populations of MDS patients will then be discussed, including those with therapy-related disease and, particularly relevant in older adults, those with comorbidities. Finally, MDS mimics – those conditions that cause dysplastic changes in the bone marrow and/or cytopenias, and may be misdiagnosed as MDS – will be reviewed.