The medical records of 15 patients found to have pneumoretroperitoneum in a 10-year period were reviewed. The cause of retroperitoneal emphysema was infection in six patients, trauma in five and iatrogenic in four. Emphysema was confined to the retroperitoneum in 11 patients, and extended to the mediastinum in four and to the soft tissue of the neck in three. Failure to diagnose pneumoretroperitoneum resulted in delayed intervention in two patients. One patient with pneumoretroperitoneum and pneumoperitoneum secondary to a lung lesion underwent unnecessary laparotomy. Outcome was favourable in these three patients. The presence of air in the retroperitoneum is not dangerous but its early recognition and detection of the source are important as septic conditions may be involved.