Laparoscopy, with the use of carbon dioxide or nitrous oxide for insufflation is a common procedure with the potential for several major complications. For example, pneumomediastinum, pneumothorax, and subcutaneous emphysema can occur singly or in any combination with this procedure. The authors report a patient in whom pneumomediastinum and massive subcutaneous emphysema developed without pneumothorax. Possible mechanisms are presented, along with discussion of the need for prompt diagnosis and termination of the procedure with deflation of the abdomen. The life-threatening potential of this complication is emphasized.