Twenty isolates of aspergillus were tested against saperconazole and 16 of these against itraconazole and amphotericin B using a macrodilution broth method. For 18 (90%) of 20 isolates tested against saperconazole, MICs were less than or equal to 3.1 mg/l and for 15 (75%) of 20 isolates MFCs were less than or equal to 3.1 mg/l. For 9 (56%) of 16 isolates tested against itraconazole, MICs were less than or equal to 3.1 mg/l, and for 4 (33%) of 12 isolates MFCs were less than or equal to 3.1 mg/l. For all 16 isolates tested against amphotericin B MICs and MFCs were less than or equal to 4.0 mg/l; for 11 of 16 isolates MICs were less than or equal to 2.0 mg/l. Saperconazole appears to be highly active against Aspergillus spp. in vitro, with a bimodal distribution of MICs and MFCs.