Background: Stroke is one of the leading causes of morbidity and mortality. Thromboembolism, as a major cause of carotid artery-related stroke, can be caused by plaque rupture which is associated with neoangiogenesis within the carotid plaque. Aim: We sought to investigate a possible correlation between angiogenesis-related factors and preoperative neurological manifestations in patients with internal carotid artery stenosis, for a better understanding of thromboembolism in internal carotid artery stenosis-related stroke. Methods: This study included 54 patients (asymptomatic, n = 20 and symptomatic, n = 34) undergoing carotid endarterectomy for high-grade internal carotid artery stenosis. In the retrieved carotid plaques, angiogenesis-related factors (vascular endothelial growth factor VEGF, hypoxia inducible factor-1 alpha HIF-1α, and Clusterin) were measured by immunohistochemistry and quantified by real-time polymerase chain reaction. Results: We demonstrated the expression of VEGF, HIF-1α, and Clusterin by endothelial cells and smooth muscle cells in the carotid plaques. Noteworthy, mRNA VEGF levels were .7-fold higher in symptomatic patients (P = .017) compared to asymptomatic patients. In contrast, mRNA Clusterin levels were 1.8-fold lower (P = .021). Levels of mRNA HIF-1α were 1.5-fold higher in asymptomatic patients, but no statistical significance was reached between the 2 groups. Conclusions: Our results show an association between VEGF and Clusterin and neurological symptoms of patients with high-grade carotid artery stenosis.