We describe a patient who developed Aspergillus tracheobronchitis after BMT. She complained of progressive dyspnea on day +165 and her respiratory function deteriorated rapidly. Although neither early chest X-rays nor CT scans were negative, bronchoscopy revealed formation of a pseudomembrane around the bronchial walls. Based upon pathological and microbiological examinations, she was diagnosed as having invasive Aspergillus tracheobronchitis. Retrospectively analyzed, the Aspergillus circulating antigen detection tests became positive before clinical symptoms developed, and may be beneficial for early diagnosis of Aspergillus tracheobronchitis. This form of aspergillosis should be regarded as one of the serious complications after BMT.