Between 2001-2002; in 62 cases, 33 (53%) male, 29 (47%) female, mean age 51.4 +/- 18.1 years) bronchoalveolar lavage (BAL) was performed for diagnosis of opportunistic pulmonary infection and specimens were evaluated for results of microbiological examinations. There was hematological malignancy in 18 (29%) and solid organ malignancy in 13 (21%) cases. Thirty-one (50%) cases were immunocompromised for reasons other than malignancy. By endoscopic evaluation endobronchial lesion was seen in 2 (3%) cases, indirect tumor signs were seen in 2 (3%) cases and signs of infection were seen in 11 (18%) cases. Forty-even (76%) cases were endoscopically normal. Acid-fast bacilli (AFB) direct examination was positive in 3 (5%) cases. In 4 (6%) cases mycobacterial culture was positive, Mycobacterium tuberculosis-polymerase chain reaction (PCR) was also positive in these four cases. Examination of gram-stained smears for bacteria was associated with infection in 14 (23%) cases. Bacteriologic cultures were positive for single potential pathogen in 10 (16%) cases, and for mixed pathogens in 7 (11%) cases for a total number of 17 (27%). Fungal cultures were positive in 3 (5%) cases all of which had hematological malignancy. As a result in 24 (39%) cases microbiological agent of infection is determined: in four mycobacteria, in 17 bacteria other than mycobacteria and in three fungi.