 Long term survivors of childhood cancer, are a distinct group requiring specific follow-up in order to enhance their quality of life. Studies have shown that many of these patients will go on to develop chronic issues within different organ systems. Because of the iron burden of the frequent transfusions required to care for these patients, iron overload may indeed be one of the problems these survivors potentially face. Research primarily in thalassemia and bone marrow transplant patients who were extensively transfused has shown that iron overload can have a significant impact on their overall health. Complications from increased iron burden can include growth retardation, gonadal dysfunction, hypothyroidism, impaired glucose metabolism, cardiac arrhythmias and failure, hepatic fibrosis and cirrhosis, and increased susceptibility to infections. However all of these conditions related to iron overload can be prevented with the use of either phlebotomy or chelation therapy. Based on this knowledge, our objective is to determine if pediatric oncology and transplant patients heavily supported with transfusions develop consequential biochemical and clinical evidence of iron overload. 