Coronary arteries are medium-small caliber vessels, in which low shear rate values are encountered, where non-Newtonian blood effects cannot be neglected. This work aims to study a comparison between Newtonian and non-Newtonian blood behaviors in a cohort offorty-eight 3D patient-specific stenotic vessels (right (RCA), left (LAD) and circumflex (LCX) coronary artery) at different grades of stenosis. Numerical simulation was carried out by means of Computational Fluid Dynamics (CFD) Analysis to investigate the blood velocity and distribution of the shear stress indices at different times of the cardiac cycle. A statistical analysis was performed to have a prediction ofincrement or decrement ofthe various hemodynamic parameters. The results show that the non-Newtonian effects are mostly important in shear stress indices distributions.