Respiratory syncytial virus infection continues to be one of the most important health problems in infancy. Active prophylaxis against this infection (i.e., vaccination) is not available. Therefore, protection of high-risk infants is possible only by passive prophylaxis with specific antibodies. Palivizumab (Synagis) and respiratory syncytial virus intravenous immune globulin are licensed by the US Food and Drug Administration for the prevention of severe lower respiratory tract infections caused by respiratory syncytial virus in infants with bronchopulmonary dysplasia, infants with a history of premature birth (< or =35 weeks gestational age) and children with hemodynamically significant congenital heart disease. Palivizumab is a humanized monoclonal antibody produced by recombinant DNA technology, directed to an epitope in the A antigenic side of the F-protein of the respiratory syncytial virus. This review discusses the characteristics of this drug in detail.