Purpose:/b＞/u＞ Respiratory Syncytial Virus(RSV) is a major cause of severe lower respiratory infection in infants and a leading cause of hospitalization for bronchiolitis and pneumonia. Immunoprophylaxis has been used in the limited high risk groups with prematurity, bronchopulmonary dysplasia, congenital heart disease. This study is to investigate the epidemiological characteristics of RSV in the neonatal period to provide information in clinical practice and suggest extension in the application of immunoprophylaxis. Method:/b＞/u＞ Neonates admitted to neonatal intensive care unit Ilsan hospital due to respiratory symptoms and performed multiple RT-PCR between October 2011 and May 2016 were included in the study. Medical records were retrospectively reviewed and data collected on 156 neonates. Result:/b＞/u＞ Among 156 neonates with lower respiratory symptoms, RSV were detected in 114(73.1%), other viruses in 25( 16%) and no virus detected in 17(10.9%). The majority were full term infants(98%) and the peak incidence of RSV infection was in January. Post-natal care center infection was common in the RSV group(53.9%) compared to other virus group(24%)(p=0.02). Clinical symptoms were severe in RSV group with more chest retraction, rale and lower oxygen saturation compared to other virus or no virus group(p0.001). Consolidation and atelectasis occurred more in the RSV group(p0.001). The RSV group frequently needed oxygen therapy(p0.001). Hospital days were longer in the RSV group( P0.005). Conclusion:/b＞/u＞ RSV is a significant cause of respiratory infection in neonates and severity is higher compare to other viral causes of infection. Most infants were born full term who were not candidates for RSV prophylaxis. Infants in post-natal care centers have high risk of RSV infections, therefore immunoprophylaxis need to be considered in this full term high risk group to prevent and reduce hospitalization.