Background: β-Thalassemia is considered as one of the most common inherited hemoglobin disorder caused by the declined synthesis of β-globin chains, resulting in ineffective erythropoiesis, subsequent chronic hemolytic anemia and iron overload. This study aimed to evaluate myocardial function in children with β-thalassemia by Speckle tracking echocardiography. Methods: A case-control study was conducted at Pediatric haematology and cardiology units, Pediatric Department, Zagazig University Hospital performed on 68 beta thalassemia patients (34 cases in each group) in the period between from February to July 2019. complete examination was done with stress on anthropometric measurements and vital signs. Laboratory investigations (CBC, Hb%, Serum iron and Serum ferritin). Echocardiographic measurements of conventional LV systolic and diastolic function performed and LV longitudinal global and segmental strain measured by 2 D speckle tracking echocardiography. Results: a significant reduction in global longitudinal strain (GLS) in thalassemic patients compared to control (-16.7±7.7 vs. -26±3.9). a significant correlation between left ventricular global longitudinal strain and serum ferritin , haemoglobin level and age of β- Thalassemic patients. Conclusion: Speckle tracking Echocardiography is superior to conventional echocardiography in giving an early evidence of myocardial dysfunction in non-symptomatic thalassemic patients. Hence, STE can be applied as an integrated part of assessment of children with beta-thalassemia.