Spontaneous pneumomediastinum (SPM) is a rare clinical entity that concerns mainly young adults. We report 13 cases (11 males/2 females) of SPM. The average age was 31 ± 0.85 years. The most common precipitating factor was asthma attack. The onset symptoms were mainly chest pain (11 cases). Synchronous pneumothorax was found in 5 cases and it was bilateral in 2 patients. The evolution was marked by the spontaneous resorption. SMP is an underrecognized cause of chest pain in young adults. Chest radiography is usually sufficient for the diagnosis, and further diagnostic procedures are generally not necessary. The prognosis is often favorable.