One of the main factors in the mechanism of cardiovascular diseases (CVD) is atherosclerosis, which is a polietiologic disorder with a beginning at childhood. An important element of the latter is endothelial dysfunction (ED). Generally accepted method of instrumental diagnosis of ED is to determine the endothelium-dependent vasodilation of the brachial artery using duplex sonography (EDVD BA), and the condition of vessel wall via assessment of intima-media thickness of the common carotid artery (CCA) (IMT CCA) and the stiffness index of CCA (β). To date, a fact of the negative impact of respiratory viruses on the endothelial function of the body vessel is considered. Given the extremely high incidence and prevalence of acute respiratory infections (ARI) in children, the aim of this work was to study the condition of vascular wall and endothelial function in these patients. It was revealed that acute respiratory infections led to endothelial dysfunction (significant decline in the FMD), which disappeared because of the inflammatory response self-limitation and did not affect the vascular wall (no change in carotid IMT and stiffness index was observed).