Abstract Background: Fragmented QRS (fQRS) might be associated with certain characteristics in ST-elevation myocardial infarction (STEMI) patients and inhospital adverse events. Materials and Methods: A sum of 500 patients were gone over retrospectively. Patients with STEMI, all undergone percutaneous coronary intervention, were grouped as fQRS (−) and fQRS (+). Characteristics of the patients, major adverse cardiac event (MACE), death in hospital, nonfatal myocardial infarction (MI), stent thrombosis, slow flow myocardial perfusion, development of ventricular tachycardia (VT) and fibrillation, cardiogenic shock and cardiopulmonary arrest were filtered. Results: FQRS (−) group was composed of 207 patients whose mean age was 61.1 ± 12.1, whereas 293 patients were there in fQRS (+) with a mean age of 66.7 ± 10.6 (P < 0.001). Thrombolysis in MI (TIMI) (P < 0.01), the global registry of acute coronary events (GRACE) (P < 0.01) scores, white blood cell count, neutrophil/lymphocyte ratio, MACE and the ratio of death in hospital and VT in the hospital were significantly higher in fQRS (+) group (P < 0.001, for remaining all). In multivariate logistic regression analysis, TIMI scores above 2 and GRACE scores above 109 were determined as independent predictors of MACE in the entire patient group (odds ratio [OR]: 2.022; 95% confidence interval [CI]; 1.321–3.424, P = 0.003; OR: 1.712; 95% CI: 1.156–2.804, P = 0.008). Conclusion: FQRS (+) and fQRS (−) patients markedly differ from each other in terms of certain demographic and clinical features and TIMI and GRACE scores have a significant predictive value for MACE in all STEMI patients’ group.