The most common cause of coronary artery disease (CAD) is vascular damage with the cholesterol built-up and other materials on the inner arterial wall, known as atherosclerosis.This paper aims to investigate the effect of stenosis on the hemodynamics in the four suspected coronary artery disease patients. Computer tomography (CT) data was acquired from patients of suspected coronary artery disease to reconstruct left coronary artery.The 3D computational simulation was carried out with four patient-specific models with area stenosis >50% located at the left anterior descending (LAD) and left circumflex (LCX) branches.The pressure, velocity and wall shear stress were calculated during the cardiac cycle. A significant pressure drop across the stenosis and increase in the velocity at the stenosis were observed at LAD and LCX branches. An increase in the wall shear stress in the region of stenosis also observed with the prevalence of the recirculation zone at the post stenosis region which results in the formation of stenosis.Our analysis provides an insight into the progression of stenosis and wall rupture, thus improving our understanding the flow behavior patient-specific realistic artery models.