The development of fungi in stored grains present a health risk to customers due to their ability to produce and accumulate mycotoxins. Then, chemical antifungal agents are applied to grains to reduce their contamination by molds. The aim of the present study was to evaluate the antifungal potency of oregano essential oil and thymol on some species of fungi involved in corn spoilage. Molds were isolated, and then identified by their macroscopic and microscopic characteristics after cultivation on standard media. The antifungal activity of oregano essential oil and tymol was conducted by broth dilution method. The mold species isolated were Aspergillus niger, Aspergillus flavus, Penicillium sp., Fusarium sp., and Mucor sp. Oregano essential oil and thymol demonstrate an antifungal effect against all these isolates. These compounds may be useful as alternative in limiting or preventing the development of harmful fungi and mycotoxins in food.