BACKGROUND Fragmented QRS (fQRS) is an electrocardiographic parameter, which could be assessed easily and non-invasively using surface electrocardiogram (ECG) and may have significant prognostic value. The present study aimed to evaluate the correlation between left ventricular ejection fraction (LVEF) and fQRS in surface ECG. METHODS This study was conducted on 186 patients with acute ST-elevation myocardial infarction (STEMI). After primary percutaneous coronary intervention (PCI) and transferring the patients to the cardiac care unit (CCU), the patients were examined using echocardiography, and ejection fraction (EF) was assessed using the Simpson's method by a single cardiologist. Data analysis was performed using SPSS software. RESULTS Among 186 eligible patients, 113 cases showed fQRS in the surface ECG. In total, 84.9% of these patients were men, and 15.1% were women (P < 0.05). No significant correlation was observed between age and fQRS (P > 0.05), as well as coronary artery disease (CAD) severity and fQRS (P > 0.05). On the other hand, a statistically significant, reverse correlation was denoted between EF and fQRS in the surface ECG (P < 0.05). In addition, significant relations were observed between the rate of ST-segment elevation and depression and fQRS (P < 0.05). CONCLUSIONS According to the obtained results, EF significantly decreased in the echocardiography of the patients with STEMI and fQRS in the surface ECG. Considering the cost-efficiency and accessibility of fQRS evaluation, it could be used for the assessment of various parameters in cardiology modalities such as cardiac magnetic resonance imaging (CMRI) and computed tomography (CT).