Two patients are reported who underwent autologous bone marrow transplantation for lymphoma and developed rapidly progressive respiratory insufficiency at posttransplant (PT) days 90 and 273. Clinical examination revealed persistent cough, exertional dyspnea, inspiratory rales, and expiratory wheezing. Results of pulmonary function studies were consistent with rapidly progressive severe respiratory disease in both patients. Despite aggressive immunosuppressive therapy, both patients had a progressive decline in respiratory function and died of respiratory insufficiency at PT days 400 and 446, respectively. Each patient had histologic evidence of bronchiolitis obliterans (BrOb). These cases demonstrate that life-threatening obliterative bronchiolitis is not limited to patients undergoing allogeneic bone marrow transplantation, but can also follow autologous transplant. Awareness that this group is also at risk for BrOb and severe respiratory compromise may lead to early diagnosis and treatment.