Background: Acute myocardial infarction (AMI) is often caused by atherosclerotic plaque rupture in one of the major epicardial coronary arteries. The difference in prognostic significance between anterior and inferior wall myocardial infarction has been thoroughly studied before. Objective: To determine the clinical, angiographic and prognostic characteristics associated with the different patterns of ST-segment changes in patients with LCX artery occlusion versus RCA occlusion. Patients and Methods: This prospective cross-sectional study included 78 patients with first presentation of acute STEMI and NSTEMI who were admitted to the coronary care unit (CCU) of cardiology department at Zagazig University hospitals in the period from January 2018 to February 2019. Patients were divided into 2 main groups; Group 1: included 41 patients with culprit lesion in LCX artery and Group2: included 37 patients with culprit lesion in RCA artery. Results: There was a significant statistical difference between studied groups regarding EF, CK MB and troponin level (ST elevation significantly higher regard EF, CK MB and troponin level than other groups). Conclusion: In patients with AMI due to culprits either in the LCX or RCA, ST elevation subgroup might be associated with 30-days MACE. Other independent predictors of 30-days MACE in such cohort include peak troponin level and LVEF. STEMI due to either a culprit in LCX or RCA may have similar 30-days MACE.