Pneumomediastinum is a rare entity that can present with varied clinical and radiological features. This paper is an analysis of radiological features in 23 consecutive cases. The location, spread and possible cause of the radiological pathology in each case by correlating with the clinical data and results of other investigations. Eleven were aged less than 40 years; youngest was 9 months old and oldest 70 years. Road traffic accidents are the most common cause. Interstitial lung disease, connective tissue disorders, surgical sequelae or cut–throat injuries are other common causes. About 10% were spontaneous. Ring around the artery and double bronchial sign are the most common named signs. Extension of air from pneumomediastinum presenting as surgical emphysema (n=19), pneumothorax (n= 18) and leak into neck (n=14) were other important features.