Background : Recent studies have shown that MDCT coronary angiography (CTCA) is useful for evaluation of acute chest pain at emergency room. The purpose of this study is to compare CTCA with EET (exercise ECG test) and to determine the role of CTCA for evaluation of chest pain on out-patient setting. Methods : We recruit patients who complaint chest pain and underwent EET and CTCA for the evaluation of CAD in out-patient clinics. The results of EET, CTCA and conventional coronary angiography (CCA) and risk factors were compared each other. The results of CTCA were divided into 5 groups: I. at least I stenosis >50%, II. plaques (stenosis <50%), III. only calcification, IV. only myocardial bridge, V. completely normal. Risk factor include age (men >45 yr, women >55yr), Total cholesterol >220 mg/dL, hypertension, current smoker and diabetes. Results : In the analysis based on CTCA, 365 patients [age 56짹1.1, men 233(63%)] were enrolled., Sensitivity and specificity of EET were 32/72 (44%) and 236/294 (80%). CTCA could divide into group I 81 (22%), Group II 72 (20%), Group III 18 (5%), Group IV 20 (5%) and Group V 174 (47%). CTCA may be more sensitive than EET for detecting significant stenosis (���50%) and plaque in the patient with 2 risk factors plaque (22% vs. 9%, p<0.001, 38% vs. 13%, p<0.001) (table 1). In the analysis based on CCA, eighty two (22%) patients with CCA included 57 patients with stenosis on CCTA and 26 patients with positive EET. The sensitivity was 45% in EET and 88% in MDCT. The specificity was 68% and 80%, respectively. Conclusion: Besides radiation hazards and economic burden, CTCA is more useful than EET to detect CAD in outpatients, especially with moderate coronary risk.