Objective: to study the clinical, laboratory and radiological features of the course of nosocomial bronchiolitis respiratory syncytial viral (RSV) etiology and effectiveness of the therapy in preterm infants in the neonatal hospital conditions. Patients and Methods: We analyzed case histories of 10 hospitalized patients who had RSV etiology bronchiolitis established by RIF/PCR in neonatal Moscow hospitals in 2011-2013. Results: RSV infection in hospitalized preterm infants with and without bronchopulmonary dysplasia runs hardly, requiring treatment in the intensive care unit, oxygen therapy and lungs mechanical ventilation. The respiratory failure is the symptom of the of RSV bronchiolitis severity. X-ray picture of the disease is characterized by peribronchial changes, emphysematous swelling, segmental infdtration and bronchial obstruction (atelectasis, hypoventilation). The frequency of bacterial complications of RSV bronchiolitis is low. In clinical practice newborns with severe RSV bronchiolitis are treated with antibiotics, bronchodilators, steroids. The timely isolation of patients can prevent the extention of the infection in the hospital. Conclusions: The preventive measures are needed to prevent the extention of RSV in neonatal hospitals, including specific immune prophylaxis of RSV infection in children at risk.