Bronchiolitis obliterans organizing pneumonia is the most serious disease of the bronchioli. An idiopathic form of the disease important for differential diagnosis in incipient forms of pulmonary fibrosis has been reported in the literature, along with other forms associated to drug use, infections, and collagen and localized diseases. We describe 3 patients with bronchiolitis obliterans organizing pneumonia, one associated with rheumatoid arthritis and consumption of gold salts, one with HIV infection and one localized form associated with pulmonary hydatidosis.