Interstitial lung disease (ILD) is a frequent manifestation of rheumatoid arthritis (RA), and it has a close bearing on the prognosis of RA patients. Computed tomography (CT) has been shown to be excellent for the diagnosis of diffuse lung disease. In this study chest radiographs and high-resolution CT (HRCT) scans were obtained in 91 patients with RA to evaluate their ILD precisely. By HRCT 43 patients could be diagnosed as having interstitial pneumonitis (IP), and 5 could be diagnosed as having bronchiolitis. The remaining 43 patients were normal by HRCT. Chest radiographic findings were consistent with the HRCT findings in approximately 50% of patients with IP. HRCT was superior to chest radiographs for the detection of early interstitial changes. The histogram of HRCT values might be a useful adjunct to HRCT diagnosis by adding some degree of objectivity. HRCT is useful for the diagnosis of ILD in patients with RA.