Platelets contribute to the pathogenesis of atherosclerosis. Platelet activation has been linked with increased mean platelet volume (MPV) and platelet distribution width (PDW). We investigated the association between PDW, MPW, and the degree of carotid artery stenosis (CS). Patients (n = 229) were divided into 3 groups according to the North American Symptomatic Carotid Endarterectomy Trial criteria. Demographic and clinical features were collected retrospectively. Correlation analysis showed a positive association between PDW and the degree of CS. However, there was no significant correlation between CS and MPV. Moreover, we observed that PDW and low-density lipoprotein cholesterol were independent predictors of the degree of CS. This study showed that PDW, not MPV, is related to the degree of CS. Platelet distribution width could be a useful biomarker for CS. Whether targeting PDW will be of clinical benefit remains to be established.