Abstract: Spontaneous mediastinal emphysema is uncommon. Its cause has not been determined precisely, but the entity is usually associated with suddenly raised alveolar pressure.Between 1980 and 2001, 114 patients with mediastinal emphysema of various causes were hospitalized in the Wolfson Medical Center. In 22 of these patients (19.3%) the emphysema occurred without an obvious preceding event and was classified as spontaneous. The commonest symptoms and signs were chest pain, dyspnea and subcutaneous emphysema. All patients were kept under observation. Contrast esophagogram was performed in two patients who vomited. Pleural drains were inserted in six patients who had concomitant pneumothorax.All patients recovered and were followed for at least one year. There were no complications and no recurrences.Spontaneous mediastinal emphysema is usually a benign condition, which can be treated expectantly. The patients should be observed for 24 h. Recurrences are rare.