Background: Because it can detect subtle myocardial damage and localize ischemic territories according to coronary lesions, speckle tracking echocardiography (STE) is a widely accessible noninvasive technique that can quickly and easily provide additional information over basic echocardiography. It also provides a clear visualization with a "polar map" that is helpful for differential diagnosis and treatment. So, we aimed at early detection of the culprit lesion site and evaluation of its severity in acute inferior myocardial infarction by echocardiography and its different modalities. Methods: This cross-sectional study was conducted at on 66 patients with acute inferior myocardial infarction in CCU, Echocardiography unit and catheterization Laboratory of Cardiology Department, Zagazig University Hospitals, Nasser Institute and National Heart Institute during the period from July 2020 to July 2022. All patients were managed according to guidelines. Results: As regards 2D echocardiographic findings, there was a statistically significant difference among our studied groups regarding end diastolic volume (EDV), end systolic volume (ESV), ejection fraction (EF), wall motion score index (WMSI) where it was statistically higher in proximal RCA than Distal RCA and LCX (p-value < 0.05). There was a statistically significant difference among our studied groups as regards GLS where it was statistically higher in proximal RCA than Distal RCA and LCX (p-value < 0.05). Conclusion: We concluded that IVC CI, GLS and Culprit Score can be considered as detectors to identify the site of the culprit lesion and its severity in cases with acute inferior wall MI.