Spontaneous pneumomediastinum or Hamman syndrome (HS) is a rare independent disease, defined as the presence of free air in the mediastinal structures and follows a benign course. Purpose. To show the difficulty of diagnosis and features of treatment in spontaneous pneumomediastinum. Materials and methods. A 4-year-old girl with a history of persistent continuous cough was conducted by a comprehensive clinical and radiological examination, including chest computed tomography (MSCT) before and after clinical monitoring, bronchoscopy and esophagoscopy. Results. Chest MSCT demonstrated a free air in the mediastinum. A course of conservative therapy was conducted after exclusion of the esophagus perforation and the left main bronchus fistula. At follow-up after 20 days - regression of a previously observed state. Conclusion. In our work, we demonstrated a case of spontaneous pneumomediastinum, illustrating the need for proper interpretation and selection of diagnostic procedures, because in the absence of complications, this condition is effectively amenable to conservative treatment.