[Introduction] NCEP-ATP III, based on Framingham risk score, is widely used guideline for primary prevention of Coronary Artery Disease (CAD). Recognizing Coronary Artery Calcification Score(CACS) as independent risk factor for CAD, newly presented SHAPE guideline recommend primary prevention for CAD based on CACS. [Method] We consecutively enrolled 1,043 South Korean asymptomatic subjects (49짹 10 years, 63% men) who underwent Coronary CT Angiography (CCTA, 64-slice MDCT) as part of a general health evaluation. Then we investigated the difference of target population for CAD prevention according to each guideline, and whether these guidelines provide adequate recommendation to the patients with occult CAD. [Result] 10 subjects were classified as very high risk and 38 as high risk patients with CACS results according to SHAPE guideline, whereas 79 subjects were classified as high risk patients according to NCEP-ATP III guideline. Considering their own LDL level, 313(30.1%) subjects needed to lower LDL level according to SHPAE guideline, and 230(22.1%) subjects with NCEP-ATP III guideline. The difference became more distinct when CACS increases; 25.8% vs 18.7% subjects with CACS of zero were recommended to lower LDL with each guideline, whereas 80% vs 20% needed to lower LDL when CACS is over 400. However, among 53 subjects, who had significant stenosis(���50%), 33(62.2%) vs 19(35.8%) subjects were recommended to lower LDL according to SHAPE and NCEP-ATP III guideline. Within the group with a CACS of zero(n=866), CCTA revealed non-calcified plaque in 40 subjects, and only 13(%) and 11(%) subjects were recommended to lower LDL according to SHAPE and NCEP-ATP III guideline. [Conclusion] NCEP-ATP III guideline omits 26.5% of the asymptomatic subjects who would be recommended to lower LDL with SHAPE guideline, and the gap was larger with high CACS. However, in case of subjects with significant stenosis or with non-calcified plaque only on CCTA, both guidelines excluded plenty of subjects from treatment. Considering the meaning of the stenosis or plaque, it is thought to be reasonable to classify these asymptomatic subjects as high risk group and recommend intensive treatment.