We report a case of neonatal pneumopericardium as a complication of continuous positive airway pressure (CPAP) delivered for respiratory distress. Pneumopericardium is the rarest neonatal air-block syndrome and is almost invariably preceded by other forms of barotrauma. There has been only one previous report of pneumopericardium complicating treatment with CPAP. In the present case there was no evidence of other forms of air block.