Background; Aortic stiffness expressed as aortic PWV is a strong predictor of future cardiovascular events and all-cause mortality. The predictive ability of arterial stiffness is higher in subjects with a higher baseline CV risk. There is a general agreement that arterial stiffness has an important predictive role. And most studies have focused on classic risk factors confined to vascular status. However, there might be some relation between blood flow and vascular wall. So, our hypothesis is that hemorheologic parameters such as blood viscosity, shear rate, and shear stress might affect to PWV as a fluid dynamic mechanism. Methods; We have measured and analyzed the PWV, hemorhelogic parameters, blood characteristics and other the clinical parameters in 538 patients scheduled coronary angiography. Results; It shows that the age, systolic blood pressure, diastolic blood pressure, pulse pressure was well correlated with PWV (r=0.56, 0.43, 0.25, 0.41, respectively. p<0.01). Additionally, the viscosity (r=-0.2, p<0.05) and the hemoglobin (r=-0.34, p<0.01) were negatively, and fibrinogen (r=0.445, p<0.01), critical shear rate (r=0.16, p<0.05) was positively correlated with PWV (Table 1). These results suggest that PWV might be affected by blood flow than the viscosity itself. This result can be explained by the Bramwell-Hill equation. Conclusion; We might suggest that flow affecting factors such as blood density including hemoglobin, shear rate, central blood pressure, and pulse pressure can affect PWV, hemodynamically. This result might provide the useful information on the characteristics of RBC aggregation and hemorheological effect on PWV.