Tortuosity is an abnormality that may occur in some arteries, such as carotid. It can reduce the blood flow to distal organs, and even in severe cases, causes ischemia and stroke. Tortuosity can be congenital or occurs due to hypertension and reduced axial pre-stretch of artery, in which case called buckling. Since atherosclerotic plaques disrupt the normal pattern of blood flow, and thus make the artery more susceptible to buckling, in this study, the effect of atherosclerotic plaques on arterial stability has been investigated using computational simulation of fluid-structure interaction under pulsatile flow and large deformation. Ideal and 3D geometry of normal and atherosclerotic carotid artery with different plaques (symmetric or asymmetric and in different percentage of stenosis) were constructed and used to simulate normal (1.5) and reduced (1.3) axial stretch ratio by ADINA. The blood flow was assumed to be Newtonian and laminar. Arterial wall was considered as an anisotropic and hyperelastic material based on the Ogden’s model. The results are verified by comparison with the available ones in the literature. It is observed that stenosis reduces the critical buckling pressure and arteries with asymmetric plaque have lower critical buckling pressure compared to the arteries with symmetric plaque. By reducing the axial stretch ratio from 1.5 to 1.3, the critical buckling pressure is reduced by 33-39 percent. Buckling increases the peak stress in the plaque and thus increases the risk of plaque rupture.