Computed tomography (CT) was compared with chest radiography in the assessment of disease severity in 27 patients with sarcoidosis. The CT scans and radiographs were each read twice by two independent observers. Disease extent was assessed on CT scans by visual scoring (0%-100% involvement of the lung parenchyma) and on radiographs by using an adaptation of the International Labour Office classification. The severity of parenchymal changes on the CT scan and on the radiograph was significantly correlated with the severity of dyspnea (r = .61 and .58, respectively; P less than .001), diffusing capacity (r = -.62 and -.52, P less than .01), and vital capacity (r = -.49 and -.51, P less than .01). Patients with predominantly irregular opacities had more severe dyspnea and lower lung volumes than patients with predominantly nodular opacities (P less than .05). The authors conclude that in patients with sarcoidosis, the radiographic and CT assessments of disease severity show similar correlation with clinical and functional impairment.