We present a case of bronchiolitis obliterans associated with juvenile rheumatoid arthritis in whom pneumomediastinum was the presenting manifestation. Diagnosis of bronchiolitis obliterans was made on the basis of the clinical history, pulmonary function tests and high-resolution computerized tomography scan findings. Pneumomediastinum resolved in a few days following high-dose nasal oxygen. This case shows that bronchiolitis obliterans can occur in patients with juvenile rheumatoid arthritis. Complicating pneumomediastinum in such cases should be considered as an indication of underlying bronchiolitis obliterans. Copyright (C) 2002 S. Karger AG, Basel.