It is known that oxidative stress can be able to induce cytotoxicity of blood cells, stimulate release of inflammatory cytokines, and induce the production of growth factors. The aim of this study was to investigate oxidative stress and endothelial dysfunction in patients with asymptomatic carotid artery disease and healthy controls. Native low-density lipoproteins, oxidised low-density lipoproteins, malondialdehyde, nitrates, glutathione peroxidase activity and endothelin-1 were determined in patients without severe (range between 30% and 50%) carotid artery stenosis. Native low-density lipoproteins, oxidized low-density lipoproteins, malondialdehyde, glutathione peroxydase, and endothelin-1 concentrations were higher in patients than in health controls (P<0.001). No difference was observed in nitrate values (P<0.8). Our results revealed oxidative stress in patients without severe carotid artery stenosis and clinical symptoms. This was shown by the elevated malondialdehyde and oxidized low-density lipoprotein levels.