The aim of the study is to present the analysis of classical head CT, Single Photon Emission CT imaging and neuropsychological tests in patients with asymptomatic internal carotid artery stenosis. A group of 10 patients was analysed. There were 3 female and 7 males aged 44-69 years (mean 61.6). In all patients high grade stenosis (above 60%) of ICA was diagnosed by using Doppler Ultrasonography. Enrolled patients had an asymptomatic course of the stenosis, they had no history of cerebral stroke or TIA incidents the neurological examination was normal in all cases. Performed CT imaging’s showed ischemic foci in 4 patients, SPECT confirmed focal disturbances of cerebral blood flow (reduced uptake or cumulation defect of marker) in 90% of cases. In the psychological assessment changes in cognitive functions were revealed in 70% of the patients. These findings suggest that asymptomatic internal carotid artery stenosis could lead to cerebral circulation insufficiency and it may be a significant factor in processes of lesions and senescence of human brain.