When the remains of an abandoned newborn are found, it is important to determine beyond a reasonable doubt whether or not the child was born alive. If the child was born alive and was developmentally capable of independent existence prior to death due to violence or failure to provide the necessary care, then the manner of death must be homicide. PIE in a newborn is a lesion acquired outside the uterus, since there is no mechanism for air entry into the lungs of an infant who is stillborn. The typical radiographic appearance of PIE is that of linear interstitial air collections. Unlike air bronchograms, they do not branch and are usually subtle and disorganized. Subpleural air collection may also be a sign of PIE. They appear as thin-walled rounded lucencies on radiographs. Intrapulmonary gas-filled spaces, pneumomediastinum, and pneumothorax also may be seen. The differential diagnostic list includes pneumatocele, diaphragmatic hernia, congenital cystic adenomatoid malformation, lung abscesses, pre-existing bullae, cavitary infarcts, and loculated pneumothorax. The case presented in this paper involved a dead newborn found near a garbage pail outside a private residence. Pre-autopsy radiographs showed a large collection of air surrounding most of the left lung, compatible with penumothorax. There were no pulmonary congenital anomalies, inspissated secretions, or foreign objects in the airways. The cause of death was attributed to smothering and compression of the neck and chest. 5 figures and 13 references