Thalassemias are group of genetic disorders (hereditary anemias) characterized by absent or deficient synthesis of one or more of the globin chains of the hemoglobin. Thalassemias are widely distributed in the mediterranean basin. In Iraq, thalassemia is carried by about 4.5-5% of the population.The most sever form is ?-thalassemia major which if left untreated will lead to death. In this book we ivestigate some immunological and biochemical changes in saliva and serum of thassemic patients and applied these changes to the oral health status.High percentage of class II malocclusion with Thalassemic Facies found in thalassemia major patients. Significant biochemical and immunological changes observed in some of the salivary and serum constituents in thalassemia major patients, as well as significant correlations found between some of these changes in saliva and the oral health status .