Respiratory syncytial virus (RSV) has been recognized as a major nosocomial hazard on pediatric wards, but symptomatic RSV infection is uncommon during the first four weeks of life. We report here four cases of neonatal RSV infection in a special-care newborn nursery and two of them probably acquired the infection nosocomially. By rapid diagnosis using immunofluorescent technique and early implementation of infection control measures, we were able to prevent further spread of RSV infection.