The authors report a case of bronchiolitis obliterans with organizing pneumonia (BOOP) pathologically proved. They give an analysis of the radiological semiologic findings on plain-film and high-resolution CT (HR-CT). In 1985, Epler proposed a nosologic status but the review of the literature and the findings of their own case give to the authors, the opportunity to discuss the entity on the clinical, evolutive, radiological and pathological point of view.