History and Objectives: Thalassemia carrier ship is fairly high in Iran and there is an increasing incidence of thalassemia major because of high rate marriage among thalassemic carriers. Due to complications associated with high concentration of Iron on the endocrine system, the present study was carried to investigate the Pituitary-Thyroid axis hormones among patients suffering from thalassemia major being treated at the Ali-Asghar hospital of Tehran in 1995.

Materials and Methods: The descriptive study was carried out on 47 patients suffering from thalassemia major (21 female and 26 male age interval 6-21 years). Hematological tests as well as HbA2 chromatographic data was used to confirm the thalassemia major. Blood samples were taken to determine T3, T4, T3uptake, TSH and Ferritin. Distribution of hormonal changes was reported.

Results: Mean value of pituitary-thyroid hormones (T3, T4, T3uptake, TSH) among thalassemic patients was similar to normal value. However value of T3 among male patients (133 ?g/dl) was lower than female patients (142 ?g/dl). T4 level was also lower among male patients (8.9 ?g/dl) compared to female patients (10.1 ?g/dl). Ferritin levels were high among all patients.

Conclusion: In high of lower growth rate among children and adolescents suffering from thalassemia major, normal function of thyroid hormones were observed. Further research on other factors, such as growth hormone, growth hormone reserves and insulin like growth hormone-1 are recommended.