Thalassemia is a common hereditary hemolytic disease caused by genetic defects regulating globin synthesis, leading to reduced or absent globin production. This results in shortened red blood cell lifespan and subsequently chronic hemolytic microcytic hypochromic anemia. Thalassemia is classified into α-thalassemia and β-thalassemia. α-thalassemia is more common and includes silent carrier state, trait, HBH disease, and Hb Bart's hydrops fetalis. The silent carrier state shows no clinical symptoms with a 2% chance of hydrops fetalis in newborns. The trait generally causes mild anemia with a 3%-5% chance of hydrops fetalis in newborns. HBH disease often presents with moderate to severe permissive anemia, typically accompanied by hepatosplenomegaly, depressed nasal bridge, and widened eye distance, giving a distinct anemic appearance. β-thalassemia is categorized into mild, severe, and intermediate β-thalassemia. Mild β-thalassemia does not show visible physical changes, mainly presenting as mild anemia. Severe β-thalassemia can exhibit extramedullary hematopoiesis causing distinctive facial features, delayed sexual development, and poor growth. The severity of intermediate β-thalassemia varies; some patients require regular blood transfusions to sustain life, allowing survival into adulthood.