ParaiParainfluenza virus is a common cause of respiratory illness among infants and young children. Although it causes severe pneumonia in immunocompromised patients, it seldom does this in immunocompetent adults. We report the case of a 51-year-old woman with no significant past medical history who presented acute respiratory distress syndrome caused by parainfluenza virus. The diagnosis was made based on reverse transcriptase-polymerase chain reaction (RT-PCR) of a respiratory specimen. The patient was successfully treated with antiviral agent combined with steroids.