Mediastinal and pulmonary localizations are found in 90% of al patients with sarcoidosis. In half the cases, the disease is not severe and is reversible without treatment. In the other half of cases, early or late respiratory complications can be seen. Early complications include subacute respiratory insufficiency by interstitial lung disease or by bronchial airway obstruction. Among late complications, the most frequent is pulmonary fibrosis. Four computed tomography patterns are found with variable functional impairments and course. Chronic obstructive respiratory insufficiency can be the consequence of specific bronchial lesions or pulmonary fibrosis surrounding proximal bronchi. Cor pulmonale is seen in 5% of cases. Aspergilloma seen in fibroemphysematous lesions can be the cause of major hempoptysis. Respiratory complications account for half of the 5% of deaths due to sarcoidosis. Respiratory complications are most often seen in radiographic stage III and IV disease. Treatments, mainly corticosteroids, only exert a suspensive effect but reduce the incidence and severity of respiratory manifestations. The gain obtained by treatment depends on the choice of the best time of institution and on the quality of monitoring. Lung transplantation is useful in most severe cases unresponsive to medical treatment.