Diabetes Mellitus is a serious complication of thalassemia major. Intensive chelation therapy in the early stage may avoid diabetes. So we aimed to determine the optimal timing age of pancreatic iron screening with MRI T2* technique. Early pancreatic hemosiderin was found in thalassemia major, with the youngest one of 5.3 years old. Early dysfunction of pancreatic exocrine and endocrine glands was found in thalassemia major, with the youngest one of 5.5 years old. Therefore, we suggest age of 5 to 6 years old as the optimal initial age for pancreatic T2* scanning.