Pulmonary complications are a major cause of morbidity and mortality in bone marrow transplant recipients. Earlier series, consisting mainly of adults, have shown evidence of obstructive changes of pulmonary functions in association with chronic graft-versus-host disease (CGVHD). We longitudinally evaluated spirometry in 46 patients who received bone marrow transplants as children or as young adults to determine whether they had similar abnormalities. Group mean FEV1/FVC, and percent predicted FVC, FEV1, and FEF25-75 values did not demonstrate obstructive changes in association with CGVHD in this patient population. Our findings suggest that younger patients with CGVHD, as a group, may fare better than older bone marrow transplant recipients with CGVHD. However, due to small sample sizes, it cannot be conclusively stated that the pulmonary function parameters analyzed do not differ in the two patient groups.