Background: Bicuspid aortic valve (BAV) is the most common congenital cardiac anomaly with 1% to 2% prevalence. The anatomic boundaries of BAV disease have been suggested including the entire proximal aorta and the pulmonary trunk. Different characteristics between BAV morphologic types have been reported. However, those findings have not been studied in Asian populations. The present study was conducted to evaluate prevalence, involved vascular segments, and morphologic difference of BAV disease in the asymptomatic Korean population. Methods: In a health screening program from 2005 to 2010, consecutive 38 BAV patients were collected. Each BAV patient (BAV group, n = 38) was matched with 3 TAV patients (TAV group, n = 114) who had the same age, gender, body surface area, and status of hypertension. In all patients, diameters of the aortic annulus, sinus of Valsalva (SOV), sinotubular junction (STJ) and morphology of the aortic valve were evaluated on echocardiography. Diameters of the ascending aorta (AA), aortic arch, proximal descending aorta (pDA), and pulmonary artery (PA) were measured, and calcification in the aortic segments and PA was examined on low-dose chest CT scan. Results: In total 23,291 patients, 38 patients (0.16 %) had BAV. Among BAV patients, 35 (92 %) were males and 3 were females (8%). Diameters of the aortic annulus, STJ, and AA in BAV group were larger than those in TAV group (23 짹 3.4 vs. 21 짹 1.6 mm, 30 짹 5.1 vs. 27 짹 2.9 mm, 42 짹 6.9 vs. 34 짹 3.9 mm respectively; p < 0.001 for all). Diameters of the SOV, aortic arch, pDA, and PA were not different between two groups. More patients in BAV group had calcification in the aortic root, AA, and PA compared with TAV group (56% vs. 10%, p < 0.001; 14% vs. 3%, p = 0.024; 11% vs. 0%, p =0.003 respectively). Presence of calcification in other segments of the aorta was not different in both groups. More than mild degree of aortic stenosis and regurgitation were more often found in BAV group (6 vs. 0 and 4 vs. 1, respectively). When compared in BAV patients with R-L type (n = 23) vs. R-N type (n = 11), diameters of the annulus, SOV and STJ in R-L type were larger (23 짹 3.9 vs. 21 짹 1.9 mm, p =0.042, 36 짹 6.5 vs. 30 짹 5.1 mm, p = 0.020; 31 짹 4.9 vs. 27 짹 4.9 mm, p = 0.014 respectively). Calcification in evaluated aortic segments or PA was more frequently observed in R-L type. (87% vs. 46%, p=0.033) Conclusion: Prevalence of BAV in a Korean population might be lower than that in western populations. Within the anatomic boundaries of BAV, the aortic root and AA were primary involved sites in terms of dilatation and calcification. Such involvements were more prominent in R-L type than in R-N type.