We have evaluated long-term pulmonary function in 14 patients who were treated for anti-glomerular basement membrane disease at our institution during the last 17 years. Eight of these patients had evidence of pulmonary involvement, as manifested by hemoptysis, pulmonary infiltrates on chest x-ray film, or anemia. These patients were compared with a control group of 15 patients who had renal disease and who were matched for degree and duration of renal disease, age, smoking history, and method of renal replacement. The following variables were measured in each patient: forced vital capacity, forced expiratory volume in 1 minute, vital capacity, total lung capacity, residual volume, functional residual capacity, single-breath carbon monoxide transfer factor, and single-breath carbon monoxide transfer factor corrected for alveolar volume (KCO). These patients also participated in a graded exercise test and measurements of oxygen uptake, carbon dioxide production, minute ventilation, and oxygen saturation were taken. Patients with anti-glomerular basement membrane disease and a prior history of pulmonary hemorrhage had a significantly reduced KCO (46% +/- 10% v 68.7% +/- 14.7%) compared with the control group. There was no difference in any of the other measured parameters.