The primary objective of this investigation was to assess the relationships between clinical characteristics, lung involvement, and frequency of pulmonary involvement in rheumatoid arthritis (RA). Using high-resolution computed tomography (HRCT) and pulmonary function tests (PFT), we prospectively evaluated 52 patients with RA (eight males and 44 females, mean age 53.6 years). The HRCT was abnormal in 35 patients (67.3%), the most frequent abnormalities being reticulonodular patterns, which were found in 22 patients (62.9%), ground-glass attenuation (20%), and bronchiectasis (17%). In this group of patients, PFT results were normal in 13 patients (37%). Titers of rheumatoid factor and erythrocyte sedimentation rate were significantly higher in abnormal HRCT presence. Higher Larsen's score, advanced age, and severe disease were significant risk factors for lung involvement (p<0.001, p<0.01, and p<0.01, respectively) and are suggested by our data to be statistically significant predictors of lung involvement in RA.