In vitro antifungal activities of itraconazole (ITZ), a new oral triazole antifungal agent, were studied against a wide range of medically important fungi including 16 genera, 37 species and 51 strains stocked in this center. The test was carried out using the agar dilution method on Sabouraud dextrose agar. ITZ showed equal or superior antifungal activities to ketoconazole against most strains of pathogenic yeasts, dimorphic fungi, non-pigmented hypomycetes, dermatophytes and dematiacious fungi. Although some strains of Candida albicans and Candida tropicalis were not completely inhibited by ITZ at concentrations up to 80 micrograms/ml, partial growth inhibitions were observed even at drug concentrations as low as 0.04 microgram/ml. The antifungal activity of ITZ against C. albicans was markedly influenced by medium composition, medium pH, inoculum size and incubation time.