The antifungal activities of equimolar quantities of three azole compounds, Bay n 7133 [1-(4-chlorophenoxy)-3,3-dimethyl-2-(1,2,4-triazole-1-yl)methylbutan-2-O1], Bay 1 19139 [1-(4-chlorophenoxy)-1-(1-imidazolyl)-3,3-dimethyl-2-butanol hydrochloride], and ketoconazole, were compared by testing the susceptibility in vitro of 10 clinical isolates each of Candida albicans, Candida parapsilosis, Torulopsis glabrata, Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, Rhizopus spp., Mucor spp., and Coccidioides immitis. Molecule for molecule, ketoconazole was consistently the most active drug. All three azoles were primarily fungistatic, although they were fungicidal at clinically relevant concentrations against some strains of A. niger.