Abstract : Thalassemia major is a serious chronic hemolytic anemia that leads to excessive iron accumulation in vital organs like the liver & the heart. This high level of iron can lead to serious cardiac complications and is the cause of high morbidity & mortality in these patients. Early evaluation of cardiac function is very important to detect those with asymptomatic functional cardiac abnormalities. To assess the effect of thalassemia on the left ventricular systolic function using conventional echocardiography. This is a cross sectional case control study conducted at the Thalassemia Center in Al-Zahraa teaching hospital/Najaf from the period of January 2022 to January 2023. Eighty five patients with β-thalassemia major who were asymptomatic for cardiac diseases & 43 healthy controls of similar demographic factors included in the study & all were examined with echocardiography to assess the left ventricular function and both groups were subdivided into 2 age groups. Twenty two cases were diagnosed with left ventricular systolic dysfunction using the Simpson method (ejection fraction ˂ 55) & 13 cases by the M-mode (fractional shortening ˂ 27). Significant negative correlation was found between the ejection fraction & serum ferritin. Increase left ventricular internal dimension in diastole is the first parameter that indicates early systolic dysfunction followed by left ventricular internal dimension in systole & reduction in left ventricular posterior wall thickness in systole, ejection fraction & fractional shortening in the following years.