Background and objective: Examination of sputum is the first diagnostic step in the evaluation of HIV-infected patients with pulmonary complications. We were interested in the indications and the diagnostic value of subsequent bronchoscopy and bronchoalveolar lavage (BAL) and especially the importance of so-called atypical bacteria. Patients and methods: We analysed 59 consecutive BALs performed in HIV positive patients with pulmonary symptoms (48 men, 11 women, age 22-70 years, 36 in stage C). Culture for Legionella pneumophila and PCR analysis for Mycoplasma pneumoniae and Chlamydia pneumoniae were done in all cases. Results: In 50 patients (85%) there was a clear indication for performing a BAL because either an infectious agent could no be detected on sputum examination (n=36), or the patient's sputum production was insufficient (n=14). In 30 (60%) of these cases bronchoscopy and BAL were able to establish a diagnosis. The most frequent agent was Pneumocystis carinii (n=12). In contrast, BAL was able to establish coinfection in patients with positive sputum samples in one case only. So-called atypical bacteria were not found. Conclusion: In patients with a clear indication, especially a nondiagnostic sputum examination, BAL plays an important role in the work-up of HIV-associated pulmonary disease. The search for so-called atypical bacteria yields unsatisfactory results.