Objective: To compare the “HEART (History, ECG, Age, Risk factors, Troponin), GRACE (Global Registry of Acute Coronary Events), and TIMI (Thrombolysis in Myocardial Infarction)” scores in predicting major adverse cardiac events (MACE) in patients reporting with undifferentiated cardiac chest pain to the Emergency Department (ED). Study Design: Cross-sectional validation study Duration and place of Study: Emergency Department, Combined Military Hospital, Rawalpindi Pakistan, from Jan to Jun 2021. Methodology: Two hundred and thirty-seven adult patients with atraumatic cardiac-like chest pain and non-diagnostic electrocardiogram (ECG) reporting to the ED were included in the study. HEART, GRACE and TIMI scores were calculated from the data. The number of patients with low risk was identified by each score and compared at a fixed safety level of minimum 95% sensitivity. The potential occurrence of MACE was confirmed using a telephonic follow-up six weeks after the presentation. Results: At an absolute safety level of minimum 95% sensitivity, the HEART score determined 101 patients as “low-risk” with 1.98% MACE missed. The GRACE score identified 49 “low-risk” patients with 4.08% MACE missed, and the TIMI score identified 66 “low-risk” patients with 3.03% MACE missed. Conclusion: Among the three scores under comparison, the HEART score performed better than the GRACE and TIMI scores at the same safety level and surpassed them in differentiating between those with MACE and without MACE.