Forty-four patients with histologically confirmed sarcoidosis were prospectively studied with high-resolution computed tomography (CT). Nodules were seen in all cases. They were isolated in 19 cases and associated with other lesions in 25 cases. Other abnormalities were irregular interfaces (n = 18, 41%), linear network (n = 14, 32%), thickening of the pleural surface (n = 9, 20%), ground-glass opacities (n = 7, 16%), lung distortion (n = 11, 25%), traction bronchiectasis (n = 3, 7%), and network of air-filled cavities (n = 3, 7%). Predominant sites of lesions were the upper and middle zones (n = 30, 68%) and posterior zones (n = 13, 30%). Nodular abnormalities were noted at CT in six cases in which the pulmonary parenchyma appeared normal on radiographs. Lung distortion was noted at CT in eight cases without visible fibrosis on chest radiographs. The majority of patients with lung distortion (nine of 11, 82%) had disease of greater than a years duration. CT improved sensitivity for the detection of all types of lesions, mainly lung distortion. Low but significant correlations were found between visual score at CT and total lung capacity, vital capacity, forced expiratory volume in 1 second, and diffusing capacity.