We correlated results of microbiologic culture and histopathologic examination for 2,891 consecutive samples from autopsy tissue, surgical or biopsy tissue, and bronchoalveolar lavage (BAL) or bronchial washing (BW) specimens. For 23 autopsy cases with suspected invasive septate mold infections by histopathologic examination, culture yielded a mold in 12 cases (52%). For 1,683 surgical or biopsy samples, histopathologic evidence of invasive septate mold infection was present in 30 samples, 9 of which also grew mold by culture (30%); 20 additional samples grew mold in culture alone, possibly representing culture contamination. Of 1,185 BAL and BW samples, mold was evident in 28 by cytologic examination and culture, 20 by cytologic examination alone, and 68 by culture alone. These results suggest a positive concordance for culture and histologic-cytologic examination of 23%, although both methods were negative in 96% of surgical and biopsy tissue and BAL and BW samples. The septate molds cultured from these samples were Aspergillus fumigatus (19), Aspergillus flavus (15), Aspergillus terreus (13), Aspergillus niger (7), Fusarium species (3), and Scedosporium apiospermum (2). A flavus was isolated significantly more frequently from tissue than from BAL and BW samples.