Background: Despite the recent advances in the medicine, triage and disposition of the patients, presenting to emergency department(ED) with acute chest pain, remained as one of the biggest medical problems. Coronary CT, which provides detailed coronary anatomy, has been suggested as a new solution for this old problem. We evaluated the diagnostic accuracy and usefulness of coronary CT in ED to evaluate the patients with acute chest pain in conjunction with other conventional diagnostic process. Method and Results: We enrolled 423 consecutive patients, presenting at ED due to acute chest pain. After initial assessment, including history, ECG and cardiac biomarkers, we classified patients into 4 groups. Group I: ischemic heart disease (IHD) was evident (n=57, 13%), Group II: IHD, highly suspected (n=45, 11%), Group III; IHD, could not be excluded (n=180, 42%), Group IV: IHD, less likely (n=141, 33%). After getting follow-up ECG and cardiac biomarkers during observational period of 2 to 4 hours, patients of Group II – IV were reassessed and 26, 26 and 13 from each group were reclassified as Group I. The disposition and final diagnosis of each group were presented in table 1. Coronary CT, myocardial SPECT and treadmill test were performed in 112, 100 and 84 patients. The sensitivity, specificity, positive and negative predictive value to detect IHD of coronary CT were 86.7/ 89.0/ 74.2/ 94.8%, those of SPECT were 89.2/ 68.6/ 73.3/ 89.7% and those of treadmill test were 68.2/ 54.8/ 38.9/ 82.9%. Conclusion: Conventional approach using symptom, ECG and cardiac markers efficiently identify high risk group of IHD. But, those classified as mid- or low-risk group need further evaluation to rule out IHD. Coronary CT showed similar or somewhat superior diagnostic accuracy compared with currently used SPECT or treadmill test. A randomized controlled trial to compare these diagnostic methods is needed.