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Background and Objective: The thalassemic syndromes are geneticaly structural disturbance of Alfa and Beta globin chains. In major Beta-thalassemia the life expectancy depended on frequent blood transfusions that lead to over storage and deposition of Iron in different body-organs (Hemochromatosis) including parathyroid glands, which may cause hupoparathyroidism. This study was done to evaluate the frequency of hypoparathyroidism in thalassemic patients referred to teaching hospitals in Hamedan – Iran. Materials and Methods: This descriptive, cross-sectional study was done on 56 thalassemic patients, which received blood transfusion. Serum Ca , P , PTH , total protein , albumin , Ferritin and BUN cratinine were checked two weeks after last transfusion. The hypoparathyroidism was defined when calcium was less than 8mg/dl and phosphorus more than 5.5mg/dl and PTH less than 10 ng/dl. Results: In this study, 14.2% of patients had hypoparathyroidism. 37.5% of hypoparathyroid ones had clinical manifestation of hypocalcemia. There were statistically meaningful association (P<0.05) between The hypoparathyroidism with desferal administration, splenectomy and diabetes. Conclusion: This study showed that the frequency of hypoparathyroidism in Beta-thalassemic patients receiving blood transfusion was relatively high, so clinical and labratory evaluation for endocrine glands specially parathyroid is recommended since early second decay of life.