Bronchiolitis obliterans organizing pneumonia is an inflammatory lung disease involving the distal bronchioles, respiratory bronchioles, bronchiolar ducts and alveoli. Its cause is generally unknown, but there are several known causes and associated systemic diseases. The clinical features include cough, shortness of breath and bilateral crackles. The vital capacity is slightly decreased, and the diffusing capacity is moderately to severely decreased. The high-resolution chest CT scan shows bilateral ground-glass opacities with air bronchograms and triangular, pleura-based opacities. Corticosteroid therapy is the best treatment option. The outcome of patients suffering from bronchiolitis obliterans organizing pneumonia is good, as up to 80% of individuals will be cured.