Background: The Global Registry of Acute Coronary Syndrome (GRACE) risk score is used to provide an estimate of 6-month mortality among patients admitted for acute coronary syndrome (ACS). Methods: This study validated the GRACE score in a contemporary cohort of 428 patients aged ≥18 years admitted to Hospital Sultanah Aminah Johor Bahru between January and April 2018 for ACS. The survival status of patients 6 months after hospital discharge was calculated using the GRACE risk score, and the validity of the GRACE risk score was evaluated by assessing its calibration (Hosmer–Lemeshow test) and discriminatory capacity. Results: Of the 428 patients in this study, 92 (21.5%) were admitted for ST-elevation MI (STEMI), 128 (29.9%) were admitted for non-STEMI and 208 (48.6) were admitted for unstable angina. By 6 months after discharge, 66 (15%) patients had died. The GRACE risk score was calibrated and validated, showing an adequate capacity for discrimination with a receiver operating characteristic area under the curve of 0.831 (95% CI [0.778–0.884]; p<0.001). Conclusion: This study validated the GRACE score for predicting 6-month mortality among patients admitted to an Asian medical centre for ACS and recommended that it is used routinely.