A previously healthy 21-year old man presented to the emergency department with sudden onset central chest pain exacerbated by breathing. A plain chest X-ray showed air within the mediastinum and pericardium confirmed by a CT scan with contrast. The patient history did not raise suspicion of any concomitant disease and the diagnosis of spontaneous pneumomediastinum with pneumopericardium was made. The patient recovered completely over the next few days with bed rest and analgesics. Spontaneous pneumomediastinum is an uncommon disease caused by rupture of perivascular alveoli causing air leakage to the mediastinum. The condition is benign and self-resolving in most cases. Pneumopericardium, a rare complication to spontaneous pneumomediastinum, is also usually self-resolving but may cause cardiac tamponade requiring intervention. Spontaneous pneumomediastinum must be differentiated from secondary pneumomediastinum caused by an underlying condition, such as esofageal rupture, trauma or infection, which may require specific treatment.