We report on 7 patients with marked idiopathic pulmonary fibrosis in the upper lung lobes. The patients were generally characterized by the following pathological and clinical features: (1) marked subpleural pulmonary opacities and reticular shadows mainly in the upper lobes, with a progressive reduction in lung volume; (2) nonspecific fibrosis (subpleural, zonal, rather well-defined fibrosis with small cysts and honeycomb lesions) in 5 patients and interstitial pneumonia in 2, mainly in the upper lobes; and (3) a slender build, and a family history of recurrent spontaneous pneumothorax. Clinically, all 7 cases resembled idiopathic upper-lobe fibrosis as described by Amitani in 1992. Further clinical and experimental research will be required to delineate the characteristics of idiopathic fibrosis affecting primarily the upper lobes.