Traditionally, mold control usually involves usage of highly toxic compounds, and this practice must be replaced with more environmentally friendly solutions (green chemistry). In this paper, antifungal activity of five newly synthesized ionic liquids (IL) was tested, in vitro. All ionic liquids are based on N-decyl- N, N, N-trimethylammonium chloride which differs only by a single substituent on a quaternary N- atom. The antifungal activity of IL was tested on Fusarium, Aspergillus, Alternaria, Trichoderma and Penicillium strains using the microdilution method by determining the minimal inhibitory and minimal fungicidal concentrations. Selected genera are major problem in food industry since they are the primary pathogens of agronomically important plants, as well as mycotoxin producers. All five IL used in this study showed antifungal effect in the range of 0.002 mol/dm3 to 0.036 mol/dm3. The greatest antifungal activity was observed when strains were treated with (C2OH)C10DMACI and (C2OOEt)C10DMACI IL. Results obtained in this study showed that all examined ILs have the potential to be used as effective antifungal agents