We retrospectively investigated the status of transfusional iron overload at Kinki University Hospital. One hundred and sixty three patients received more than 10 red blood cell (RBC) units per year in 2009 and 2010. Myelodysplastic syndrome (37.4%) and aplastic anemia (11.0%) accounted for about 50% of the underlying diseases. At the time of receiving a total of 20 RBC units, 90.8% and 66.2% of the 65 patients evaluated had more than 500 and 1,000 ng/ml of serum ferritin, respectively. The frequency of organ dysfunction associated with iron overload was 56.9% of all the patients assessed, 37.8% of patients with serum ferritin levels of 500∼999 ng/ml, and 67.4% of patients with serum ferritin levels >1,000 ng/ml. Although the Japanese guidelines propose 40 units of RBC transfusion and/or a serum ferritin level of 1,000 ng/ml as a good point to start iron chelation therapy, our results suggest that iron overload and consequent organ dysfunction may occur earlier than this. Therefore, it may be necessary to start iron chelation therapy earlier than that suggested by the Japanese guidelines.