Article abstract: Lung contusion is an entity involving injury to the alveolar capillaries, without any tear or cut in the lung tissue. Blunt chest trauma and related complication is associated with 25% mortality. Lung contusion is one of the most dangerous complications of blunt chest trauma and occurs in 25-75% of all blunt chest traumas. PubMed, Elsevier and Medline search with two keywords, lung contusion and chest trauma, was done till 2016 for the most important questions. Despite of decrease in the prevalence of lung contusion, the mortality and morbidity of this entity have not been improved during the last decades, due to misunderstanding of pathophysiology.