Background: Worldwide, coronary heart disease (CHD) is topping the foremost important chief causes of mortality. Fragmented QRS (f-QRS) is a pattern of QRS complex in 12 leads surface ECG which showed a promising value in predicting the outcome in cardiac diseases including ischemic heart disease. We aimed to research the importance of using f-QRS as a non-invasive and cheap tool for the prediction of cardiogenic shock and mortality in acute coronary syndrome (ACS). Methods: A retrospective study includes eighty four critically ill ACS patients. Patients were classified consistent with the presence or absence of fragmented QRS into two groups (46 and 38 patients respectively). Exclusion criteria include past history of important ischemic events (MI, PCI, and CABG), permanent AF, and/or cardiomyopathy. No statistical significant differences were detected between the 2 groups as regards the age, gender, major risk factors of ischemic heart condition, cardiac bio-markers, Killip class, LVEF, updated GRACE risk score of ACS, and inhospital mortality. Results: A number value of f-QRS leads > 3 yields sensitivity and specificity (83.3% and 72.5% respectively) for predicting hospital mortality. The f-QRS group was further split-up according to the numbers of f-QRS leads into 2 subgroups; subgroup (A1) including patients with > 3 f-QRS leads and subgroup (A2) including patients ≤ 3 f-QRS leads. Subgroup (A2) showed considerable difference as regards some important variables including a higher SBP (P = 0.016), a slower HR (P = 0.014), a lower updated GRACE risk score (3.22 ± 6.95 vs 6.81 ± 12, P value 0.048), and a lower rate of hospital death (1/30 vs. 5/16, P = 0.015). Anterior f-QRS showed statistically significant higher HR, lower SBP, a higher frequency of shock, a higher updated GRACE risk score, and a higher chance of in-hospital mortality (P = 0.004) compared to non-anterior f-QRS. Conclusion: The position and number of f-QRS leads provide a non-invasive and a readily accessible tool to predict the prognosis, occurrence of cardiogenic shock, and in-hospital mortality.