Transfusion dependency is an independent prognostic factor in myelodysplastic syndromes (MDS). The detrimental effect on survival is related to the severity of transfusion requirement and is more noticeable in low-risk patients. Elevated serum ferritin levels have a poor prognostic impact on the survival of transfusion-dependent patients with refractory anemias, and can adversely affect the outcome of patients with MDS receiving allogeneic stem-cell transplantation. Sequential measurements of serum ferritin are useful for measuring secondary iron overload in MDS patients. The implementation of non-invasive methods for assessing tissue iron and organ function should clarify the impact of iron-mediated organ damage on patients with MDS.