In patients with chronic renal failure, mechanical and hemodynamic changes could occur in the lung without obvious pulmonary symptoms and findings and their effects could pave the way to pulmonary functional disorders. In this study, pulmonary functions were assessed in 50 uremic patients on conservative treatment and on haemodialysis without any lung disease or pulmonary edema symptoms and findings. The spirometric values were affected in those patients as well as carbon monoxide diffusion capacity of the lung with preservation of lung volumes. Even though the uremic patients did not show any symptoms, their pulmonary function tests were found to be disturbed.