Objective: With the increased incidence and prevalence rates of ST-segment elevation myocardial infarction (STEMI), emergency physicians (EPs) are expected to diagnose STEMI accurately and quickly based on electrocardiograms (ECGs) with minimal clinical information. However, a misdiagnosed ECG by EPs could be diagnosed as STEMI by a cardiologist. We evaluated the diagnostic performance of EPs in interpreting ECGs of STEMI in terms of the agreement of this diagnosis with that of a cardiologist. Methods: This study was performed using 122 de-identified ECGs of STEMI patients who had their diagnosis confirmed through emergent coronary arteriography and percutaneous coronary intervention. Three EPs and a cardiologist participated in the survey. For each ECG, physicians were asked, “Based on the ECG provided, is there ST elevation, ST depression, or no ST-segment change?” The overall agreement for ST change diagnosis between the EPs and a cardiologist was analyzed using Cohen’s kappa coefficient (κ). Fleiss’s kappa was used to determine the level of agreement of the three EPs. Results: There was a substantial level (k>0.6) of inter-rater agreement of the ECG interpretation (IRAE) between the EPs and the cardiologist and between the three EPs. However, in subgroups according to the culprit artery for the overall STEMI ECG, the level of IRAE between the EPs and a cardiologist and between the three EPs was substantially lower (k<0.6) when relating to the anteroseptal wall due to occlusion of the left anterior descending artery. Conclusion In evaluating STEMI ECGs, the accuracy of the EPs suggests a substantial level of IRAE relating to the lateral and inferior wall and a relatively low level of IRAE with respect to the anteroseptal wall.