It was considered the influence of severity of lung injury on the course of traumatic disease in combined trauma of the chest. It is established that the extensive damage to the lung parenchyma make the greatest contribution to the course and the outcome of traumatic disease in combined injuries of the chest with lung injury. Such damage prevent normal gas exchange, leading to disturbances in the system of transport of blood gases and, as a result, hypoxemia, acute respiratory failure of different degree, as well as to the development of systemic inflammatory response syndrome. These violations occur in patients with extensive lung injury as early as within acute period of traumatic disease, and in the second and third periods are the most pronounced. This group of patients is characterized by a high incidence of visceral and generalized bronchopulmonary infectious complications, higher mortality. The pulmonary complications and sepsis are the main cause of lethal outcomes in patients with extensive lung injury. At the same time, the course of traumatic disease in its clinical manifestations, the dynamics of the severity of the condition, complications and outcomes in patients with limited lung injury is the same as in patients with Multisystem injuries of the chest without injury of the lungs. Thus, one of the main factors that have influence on the course of traumatic disease, the incidence of visceral and generalized complications, and mortality in patients with closed injury of the chest, is the volume of damaged lung parenchyma (that is, its extent), or the severity of lung injury.