Background Late infarct size (IS) after STEMI is a determinant of subsequent mortality. Late Gadolinium enhancement in cardiac magnetic resonance imaging (LGE-CMRI) is the gold standard for IS measurement, however, it is not readily accessible in many areas. Aims To evaluate the value of early baseline 2D-echocardiographic global longitudinal strain (GLS) for prediction of late IS after STEMI. Methods From October 2017 to July 2018, we studied 100 patients with their 1st anterior STEMI treated with a PPCI. Baseline GLS calculation was performed within 48 hours of admission. The average value of the 9 segments supplied by the LAD was assessed separately (anterior GLS). Infarct size was assessed 3 months later using LGE-CMRI, and large infarcts were defined as ≥20% LV myocardium covered by scar. Results Based on CMRI, patients were divided into 2 groups; 57 patients with large infarcts (group I) and 43 patients with small infarcts (group II). Both groups were matched in all baseline demographics and risk factors. There was a good and significant correlation between GLS and the degree of myocardium affected by scar (r=−0.840, P