We describe a ventilated preterm infant (26 week's gestation) who developed severe right-sided pulmonary interstitial emphysema following Staphylococcus aureus pneumonia. Prolonged selective bronchial intubation (10 days) resulted in a marked clinical improvement and resolution of the emphysema. Resolution of unilateral pulmonary interstitial emphysema may require a longer course of selective bronchial intubation than currently recommended.