To evaluate the findings on thin-section computed tomographic (CT) scans in desquamative interstitial pneumonia (DIP), the CT scans from 22 patients aged 22-71 years (mean age, 43 years) were reviewed. In all patients, DIP was proved with open-lung biopsy performed 1 day to 17 months before or after examination with CT (median interval, 1.5 months). The lungs were divided into three zones (upper, middle, and lower); each zone was evaluated separately. The predominant finding was the presence of areas of ground-glass attenuation that involved the middle and lower lung zones in all patients and the upper lung zones in 18 patients (82%). Such areas had a lower lung zone predominance in 16 patients (73%) and a predominantly peripheral distribution in 13 patients (59%). Irregular lines of attenuation suggestive of fibrosis were seen in 11 patients (50%) and cystic changes, in seven patients (32%). The distribution of abnormalities in DIP is similar to that seen in usual interstitial pneumonia (UIP), but the greater extent of ground-glass attenuation and the paucity of cystic changes in DIP should enable distinction from UIP in most patients.