Bronchiolitis obliterans (BrOb), a late complication of bone marrow transplantation (BMT), is associated with chronic graft-versus-host disease (GVHD) and is frequently fatal. To identify the risk factors associated with BrOb, the factors affecting survival, treatment outcomes, and causes of death of patients with BrOb, we retrospectively analyzed 2859 BMT recipients. No cases of BrOb occurred among 1070 autologous BMT recipients. Among 1789 allogeneic BMT recipients, we identified 47 patients with BrOb. In multivariate analysis, older recipients or donors and acute GVHD were significantly associated with the development of BrOb. Among patients with BrOb, 5-year survival from the time of transplantation was only 10%, versus 40% among allogeneic BMT recipients without BrOb. The clinical course of BrOb had a significant effect on survival: 79% survived 5 years from the time of BrOb diagnosis if BrOb improved versus 13% if there was no improvement after the first-line therapy. Predictors of response included older donors and recipients, a previous diagnosis of chronic GVHD, and diagnosis of BrOb 6 months after transplantation; each of these significantly increased the likelihood of a favorable response to treatment. BrOb had high mortality rate of 55%, and pulmonary failure was the leading cause of death. More effective BrOb therapy is needed, especially for patients with unfavorable presentation.