1. Intrapulmonary interstitial emphysema is a common and important complication of hyaline membrane disease. 2. It is suggested that the progression of intrapulmonary interstitial emphysema may lead to the development of other early complications of hyaline membrane disease, such as pneumomediastinum, pneumopericardium, extrathoracic air, and pseudocyst formation in the lungs. 3. The observation of intrapulmonary interstitial emphysema should alert the radiologist and the clinician of the possible subsequent development of other complications, particularly a pneumothorax.