The results of comparative analysis of epidemiological, clinical and laboratory indicators in 317 children in the age from 1 month to 5 years with acute respiratory syncytial virus infection (АRSVI) with the lower respiratory tract lesion are presented. All the patients were comprehensively examined for АRSVI. Only 29 children (10% of the surveyed patients) had no RSVI markers. Clinical and laboratory signs of acute RSVI were identified in 220 children (68,7%). In children of the first year of life АRSVI was confirmed by the viral RNA detection in the oropharynx strokes in 65% of cases. In children of the second year of life ARSVI was confirmed by detection of the viral RNA and RSV antigens in the oropharynx strokes equally frequently (52% and 54%). In patients over the age of two years the diagnosis was based on the RSV antigens (66%) and specific IgM (36%) detection. In most hospitalized children the disease has been proceeded in moderate form. Severe forms have been generally detected in children of the first year of life (8,6%). In children of the first year of life ARSVI has been often proceeded with the bronchial obstruction syndrome (63%), and only in this group bronchiolitis has been developed (12%). The frequency of ENT-organs lesion increased in children aged 2 to 5 years and the disease has been proceeded mainly with the pneumonia symptoms. The maximum viral RNA detection in children of the first year of life was recorded in November-February 2012, with the re-increase in May 2012. In patients aged 1,1 to 2,0 years the ARSVI markers have been detected evenly throughout the year of observation, excluding the summer months. In the group of children of the pre-school age (2,1–5,0 years) the hospitalization rate for the RSVI increased significantly in September-October 2011, and the frequent virus excretion was maintained during the summer months in patients with the lesions of the lower respiratory tract.