The antifungal activity of the synthesized cyclic peptides (1a-16a, 1b-16b, 1c-24c, 1d-24d, and 1e-11e) was determined against A. fumigatus (Af-293) and two different strains of C. albicans (ATCC 60193, ATCC 10132) and one strain of C. krusii (ATCC 6258). The observed MICs are illustrated in Figure and Table in Supporting Information. Compared to A. fumigatus, Candida strains showed greater susceptibility against all the tested peptides. All peptides displayed good to moderate activity against A. fumigatus with MICs in the range of 12.5-50 µg/mL. Except for a few peptides that showed the highest activity against C. Krusii with MIC = 1.5 µg/mL, most of the tested peptides showed activity against Candida strains with MIC = 3.1-6.2 µg/mL.