BACKGROUND Pneumomediastinum is a rare complication of anorexia nervosa. It may occur in patients with severe weight loss and a history of induced vomiting. METHODS A 14 year-old girl was admitted suffering from severe anorexia nervosa. Shortly after admission, she complained of anterior thoracic pain. Examination showed subcutaneous emphysema of the supraclavicular fossae and the base of the neck. Thoracic X-ray showed pneumomediastinum without pneumothorax. At the time, the patient admitted to a history of surreptitious chronic induced vomiting. Gastrografin esophagography ruled out an oesophageal tear. The pneumomediastinum gradually disappeared over a period of several days with simple clinical and radiological monitoring. CONCLUSIONS This case, along with seven others reported in the literature, confirms that pneumomediastinum in anorexia nervosa is usually not accompanied by pneumothorax. An oesophageal perforation must always be ruled out. Spontaneous pneumomediastinum invariably has a favorable outcome.