BACKGROUND Rheumatoid Arthritis (RA) is a chronic systemic inflammatory disease characterized by persistent synovitis of most of the peripheral joints. Pulmonary involvement is one of the important extra articular features of RA with worse prognosis. Current research aimed to compare the pulmonary function test abnormalities in RA patients-treatment naïve versus patients on treatment. MATERIALS AND METHODS 50 rheumatoid arthritis patients were divided into two groups-treatment naïve group & on treatment group and evaluated for lung involvement by spirometry. Those patients showing lung function abnormalities were evaluated for correlation with various characteristics like age, gender, duration of treatment, pattern of PFT abnormality and the severity of arthritis. RESULTS PFT abnormalities were found in more than half of RA patients with restrictive pattern of lung disease being the commonest abnormality in females. There is increased prevalence of PFT abnormality in 'on treatment' group when compared to treatment naïve group. CONCLUSION Lung involvement is one of the most important extraarticular manifestations of rheumatoid arthritis. Pulmonary function test (PFT) helps in identifying the lung involvement and its pattern in rheumatoid arthritis patients.