Background: The ECG is sensitive and valuable in detecting coronary artery disease. However lead aVR is frequently ignored, as most clinicians believe that it merely represents reciprocal changes from leads (aVL, II, V5, and V6). Therefore, using it solely to guarantee the correct placement of other leads. Even with this unjustified neglect, we know nowadays that lead aVR is very sensitive not only to locate obstructed coronary arteries but also for risk stratification. Objectives: To estimate the prevalence of ST segment elevation in lead aVR in acute myocardial infarction (MI) and to evaluate the significance of this ST elevation in localizing the culprit vessel and in prediction of major adverse cardiac events (MACE) during hospitalization. Patients and Methods: This is an observational prospective study that included 120 consecutive MI patients admitted to coronary care unit. Both ST elevation MI (STEMI) and non-ST elevation MI (non-STEMI) were included. Patients with ECG confounders (left bundle branch block, right bundle branch block and ventricular paced rhythms) were excluded. ST-elevation/depression in lead aVR of 0.1mV or greater was considered significant. Patients were divided into 3 groups according to lead aVR ST-segment: patients with no aVR ST deviation, patients with aVR ST elevation and patients with aVR ST depression. Results: The mean age of the population studied was 56.6 ± 8.7 years. Male sex was predominant n= 86(71.7%). STEMI was the diagnosis in 73(60.8%) patients. Thirteen patients (10.8%) had aVR ST elevation and 14(11.7%) had aVR ST depression. Those with aVR ST elevation were older in age 62.4 ± 10.8 years vs 56.0 ± 8.3 years in those with no aVR ST deviation (p value= 0.01). Only one patient (7.7%) with aVR ST elevation had MACE in the form of cardiogenic shock. The number of vessels significantly affected was higher in patients with aVR ST elevation (p value= 0.02). Three patients (23.1%) had single vessel disease with the left anterior descending artery (LAD) being the culprit vessel in all of them. Conclusion: There was no relation between aVR ST elevation and MACE during hospitalization. Lead aVR ST elevation predicts higher number of vessels being significantly affected or LAD as the culprit vessel in those with single vessel disease.