Objective: To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production. Method: In vitro antifungal and antiaflatoxigenic activity of essential oils was carried out using poisoned food techniques, spore germination assay, agar dilution assay, and aflatoxin arresting assay on toxigenic strains of Aspergillus species. Results: Cymbopogon martinii, Foeniculum vulgare and Trachyspermum ammi (T. ammi) essential oils were tested against toxicogenic isolates of Aspergillus species. T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 μl/mL by essential oils of T. ammi. The oil also showed, complete inhibition of spore germination at a concentration of 2 μl/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting aflatoxin production from Aspergillus niger and Aspergillus flavus at 0.5 and 0.75 μl/mL, respectively. Cymbopogon martinii, Foeniculum vulgare and T. ammi oils as antifungal were found superior over synthetic preservative. Moreover, a concentration of 5 336.297 μl/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity and strengthening its traditional reputations. Conclusions: In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by storage fungi.