Human respiratory syncytial virus (RSV) is a major causative agent of respiratory infections. Common cold syndrome caused by RS virus, which is prevalent in winter, occasionally develops into bronchitis, bronchiolitis and pneumonia. In particular, severe RS virus infections in infants with underlying cardiopulmonary diseases and with low-birth weight baby have been a problem. Furthermore, repetitive RS virus infections occur for the entire lifetime, and the relationship between RS virus infections and exacerbation of COPD and bronchial asthma is also indicated mainly in elderly individuals. Various immunomodulatory effects other than antimicrobial activity of macrolides, including clarithromycin, have been reported, and their clinical usefulness is shown mainly in respiratory diseases. This review describes the findings of action of macrolides on RS virus infections.