To examine the therapeutic consequences of diagnostic tests for AIDS-related infections, case records from 33 deceased AIDS patients were reviewed; 23 were autopsied. Determination of serum antibody titres was not important. In particular, there was no relation between titres and isolation of cytomegalovirus (CMV); isolation attempts or possibly antigen determination would be better. Samples for CMV isolation were obtained from 31 patients; only 7 were negative. Blood, faeces, and particularly sputum cultures gave a low yield; the number of such examinations could be reduced considerably. However, 4/7 disseminated infections with atypical mycobacteria were only revealed at autopsy, despite numerous cultures in vivo. Liver biopsies were not helpful. Diagnostic procedures for Pneumocystis carinii pneumonia by lung biopsy caused pneumothorax in 3/15 patients; bronchoalveolar lavage or treatment/prophylaxis without diagnosis could be considered. In 8 autopsies, microscopy was suggestive of cerebral toxoplasmosis, but only 1 patient had presented important clinical symptoms. We suggest a schedule with regular microbiologic and parasitic examinations and few antibody tests, but with more antigen tests.