The in vitro activity of itraconazole, fluconazole and amphotericin B was tested against 207 yeast strains and 3 Aspergillus fumigatus strains isolated from blood. The other 42 A. fumigatus strains were selected from respiratory tract infections. A microdilution method was employed to determine the inhibitory concentrations to restrain 70% of isolate growth (IC30). The inhibition concentrations of amphotericin B are all around the value 0.25 mg/l with a deviation of two concentration degrees, indicating sensitivity of all strains. The test results of itraconazole showed the majority of strains in the range of sensitivity (200 isolates) and low sensitivity (44 isolates). Five of 19 Candida glabrata strains demonstrated resistance to itraconazole. The results of fluconazole showed a good sensibility of C. albicans, but 4.5% of strains were resistant. Low sensitivity (1 strain) and resistance (24 strains) were evaluated for C. glabrata and C. krusei isolates. No strain of A. fumigatus was inhibited by fluconazole. The data show the necessity of in vitro tests.