The myelodysplastic syndromes (MDS) encompass a hematologically diverse group of neoplastic disorders with a common pathological and clinical phenotype but distinct underlying biology and variable outcome. The prognosis of MDS depends on disease risk features, host factors, and their interaction. Risk stratification allows forecasting of disease prognosis and tailoring patient treatment based on that risk. The International Prognostic Scoring System (IPSS) served as the first widely adopted model for several years. New risk models, including the M.D. Anderson risk model and revised IPSS, refine the prognostic power of the IPSS and address some of its shortcomings. We are learning more about the biology of the disease by uncovering the various genetic and molecular mutations. Those in turn, serve as prognostic factors and will be incorporated in the new risk models.