Transfusion dependency is known to cause endocrinopathies in patients with thalassaemia such as adrenal insufficiency, because transfusion-related iron overload is injurious to endocrine organs. Children with HbE/ß-thalassaemia vary greatly in red cell transfusion requirement and some are transfusion dependent (TD), whereas others are nontransfusion dependent (NTD). Because iron overload is thought to be the primary cause of adrenal insufficiency, TD children with HbE/ß-thalassaemia are considered likely candidates for the development of adrenal insufficiency, while the adrenal function of NTD children is generally considered to be normal. As yet, the prevalence of adrenal insufficiency among children with NTD HbE/β-thalassaemia is not known. The present study was performed to (i) assess the prevalence of adrenal insufficiency in children with both TD and NTD HbE/β-thalassaemia and to evaluate whether there is any difference in the prevalence of adrenal insufficiency between both groups and (ii) determine the type of adrenal insufficiency (primary or secondary).