Bronchoscopy obtaining bronchoalveolar lavage (BAL) fluid and bronchial secretions (BS) and/or high-resolution computed tomography (CT) of the lungs were performed in 33 patients with pulmonary aspergillosis from 1987 to 1992. The sensitivity of BAL fluid or BS for detecting histologically proven fungal disease was 33 and 50%, respectively, whereas positive serologies were only documented in 8% of the cases. CT scans contributed to the early diagnosis of opportunistic fungal pneumonia: characteristic CT signs were found in 16 of 19 episodes. The more frequent use of bronchoscopy and CT scans between 1990 and 1992 compared to 1987-1989 for the differential diagnosis of new pulmonary infiltrates resulted in earlier appropriate treatment. The average introduction of intravenous (i.v.) antifungal therapy after the onset of pneumonia was shifted from 12 to 7 days (p < 0.05). The timely implementation of i.v. antimycotic therapy had a significant impact on survival. Initiation of antifungal treatment later than 10 days after the onset of pneumonia resulted in a mortality of 90%, as opposed to 41% with an earlier start of antimycotics (p < 0.01). The earlier use of appropriate antifungal therapy in the second treatment period improved survival from 33 to 50% (NS). Bronchoscopy and high-resolution CT scans are mutually complementary diagnostic tools and should be performed as early as possible in the course of pneumonia for patients at high risk for aspergillosis.