Background: Chest pain representing acute coronary syndrome (ACS) is the most common reason patients presenting to the emergency department (ED) are admitted to the hospital. This study was a prospective validation of the HEART score for chest pain patients at the emergency department. Materials & Methods: Patients admitted to the cardiac emergency department due to chest pain irrespective of age were included in the study. Complete patient history was taken. Only the troponin value of the first blood sample was used for the HEART score calculation. The primary endpoint in this study was the occurrence of a major adverse cardiac event (MACE), within six weeks of initial presentation. Statistical analysis was performed with R (Version 2.9; The R foundation for Statistical Computing, Vienna, Austria).