A 48-year-old woman was admitted with dyspnea on effort. She suffered from adult T-cell leukemia and received peripheral blood stem cell transplantation (PBSCT). Eight months after the PBSCT, she developed dyspnea on effort and was treated with bronchodilator, inhaled corticosteroid, anti-leukotriene drug, theophylline and oxytropium bromide. However her symptoms progressed and she was admitted. We diagnosed bronchiolitis obliterans syndrome (BOS) because of obstructive pulmonary dysfunction, diffuse patchy high density of the lung field on chest computed tomography and decreased ventilation with peripheral patchy accumulation on ventilation scintigraphy. She was treated with corticosteroid and cyclosporine A and her symptoms and her pulmonary function were improved. However, in parallel with corticosteroid tapering, her symptoms and pulmonary functions worsened. Treatment with Tiotropium bromide was started and her pulmonary function improved significantly. Her pulmonary function did not worsen and tapering steroid dose was successfully achieved. PBSCT was reported to up-regulate the muscarinic receptor activity in lung. Tiotropium bromide might become one additional option for the treatment of BOS.