Pneumomediastinum is an uncommon condition characterized by the accumulation of air in the mediastinum. The condition is frequently associated with other forms of extra-alveolar air, including pulmonary interstitial emphysema, pneumopericardium, pneumothorax, subcutaneous emphysema, pneumoretroperitoneum, and pneumoperitoneum. In addition, the majority of affected patients have predisposing factors that cause an increase in airway pressure, leading to alveolar rupture. Despite the numerous reports on the condition, its incidence in adult patients with asthma exacerbations remains widely underreported. A recent report examined 45 patients with severe acute asthma exacerbations who underwent radiologic imaging on admission and found that 11% had pneumomediastinum. Meanwhile, in this case report, a 23-year-old male patient with a chief complaint of shortness of breath was diagnosed with pneumomediastinum due to uncontrolled asthma. After mediastinoscopy was performed, the complaint was significantly improved.