Lobar emphysema in the neonate is usually congenital, resulting from cartilage deficiency causing bronchomalacia and distal air trapping. Acquired forms are usually associated with chronic lung disease or endobronchial obstruction such as mucus plugging. We report a pedunculated endobronchial polyp in a 2-month old ex-premature infant causing intermittent hyperinflation of the right middle lobe. The polyp was seen prolapsing in and out of the bronchus intermedius at bronchoscopy. Possible aetiological links with mechanical ventilation are discussed. We also emphasise the value of bronchoscopy prior to lobectomy in cases of congenital lobar emphysema (CLE).