Thalassemia is an inherited blood disorder in which the body makes an abnormal form of hemoglobin. Hemoglobin is the protein in red blood cells that carries oxygen. The disorder results in large numbers of red blood cells being destroyed, which leads to anemia. Thalassemia is inherited as an autosomal recessive disorder. Beta thalassemia is caused by deficient synthesis of beta chain with normal alpha chain synthesis. Alpha thalassemia is caused by deficient synthesis of alpha chain with normal beta chain synthesis. Defect may occur at different steps of beta chain synthesis such as splicing mutations, chain terminator mutations and promoter region mutations. The most common cause of reduced alpha chain synthesis is deletion of alpha globin genes. These defects causes ineffective erythropoiesis and destruction of red cells due to cell membrane damage and decreased deformability leading to extravascular hemolysis. Anaemia leads to several additional problems such as erythroid hyperplasia in bone marrow, skeletal deformities, iron overload, secondary haemochromatosis, cardiac failure, endocrine defieciency and even death. The aim of the study was to find out the incidence of thalassemia in different blood groups as well as various age groups. Total 128 diagnosed cases of Thalassemia were selected, their ABO blood grouping and Rh typing was done and the results were compiled into various categories. The disease was most commonly found in blood group B (39.77%) with predominance of  males aged between 0–5 years (42.18%).