A 2,100 gm (4 lb 10 oz) infant with respiratory distress syndrome developed a spontaneous pneumopericardium on the second day of life. Although this was associated with some increase in respiratory distress, there were no signs of cardiac tamponade. The child was kept in an atmosphere of high oxygen concentration for a few hours with prompt improvement of respiratory symptoms. The pneumopericardium was completely resolved within 48 hours. Although pneumopericardium is a rare occurrence in the neonatal period, it is important to recognize this complication, as fatal cardiac tamponade may occur. Although one should have a needle, syringe, and stopclock at the bedside, it is possible that many cases will not require aspiration and that conservative management with high oxygen atmosphere will result in prompt reabsorption of the air. The development of bradycardia and circulatory failure would encourage one to relieve the tamponade.