Backgrounds: In patients with asymptomatic aortic stenosis (AS), exercise testing may help to stratify the clinical risk. However, data are limited and abnormal response still rely on clinical indices such as symptom, blood pressure (BP), saturation and ECG changes. The study was undertaken to analyze indices of 2D Doppler echocardiography (2DEcho) that coincide with clinical indices for abnormal response during exercise echocardiography. Methods: The study included 8 patients (mean age 62.2 yrs, male 4) with asymptomatic, moderate or severe AS according to ASE guideline. All patient were performed symptom limited graded bicycle exercise in a semi-supine position on a tilting exercise table allowing continuous 2DEcho. The exercise test was considered to be abnormal when angina, dyspnea, 2mm ST depression, or fall or small rise of systolic BP were appeared as compared with baseline. Aortic valve area (AVA), maximal transaortic pressure gradient (PG max), mean transaortic pressure gradient (PG mean), ejection fraction (EF), systolic and early diastolic tissue velocity on mitral annulus (S��� and E���), maximal velocity of tricuspid regurgitation (TR Vmax), peak systolic pulmonary artery pressure (sPAP) were measured at baseline, 25Watt, 50Watt, 75Watt and 100Watt, respectively, and then the difference between maximal and baseline value was calculated. Results: Abnormal response group had significantly more peak Vmax (4.10짹0.9 vs 3.90짹0.14, p=0.04), maximal PGmean (41.03짹16.5 vs 33.68짹6.1, p=0.03), differences of PGmean (14.6짹2.7 vs 11.9짹6.2, p=0.02) than normal response group. However, EF, S���, E���, TR Vmax, sPAP, AVA and its difference were not different between two groups. Conclusions: When exercise echocardiography is performed for asymptomatic but significant AS, maximal Vmax and maximal PGmean must be considered as well as clinical indices for the decision of abnormal response.