BACKGROUND: Microbial growth and unfavorable taste and aroma are the leading reasons of meat spoilage under refrigerated temperatures. Today, plant essential oils are good alternatives to synthetic preservatives. In the meantime, nanotechnology has been instrumental in helping to apply the most effective plant compounds on the target cell. OBJECTIVES: The present study aimed to identify the compounds of essential oil of Cuminum cyminum and to investigate the microbial counts (total count, psychrotrophs, lactic acid bacteria, mold and yeast) after preparation of nanoemulsions of cumin essential oil via ultrasonic method and its nanoemulsions. Moreover, herein, we intended to evaluate organoleptic in chicken fillet samples under temperature of 4 °C. METHODS: The essential oil components were analyzed with GC / MS and the effects of Cuminum cyminum essential oil nanoemulsion were examined on microbial count and organoleptic properties in terms of color, odor, and overall acceptance (with 9-point hedonic scale) on Cuminum cyminum EO nanoemulsions in chicken fillets under 4 °C. RESULTS: The major identified components of Cuminum cyminum by extraction time were: beta- pinene (8.90 %), benzene- methyl (16.51 %), gamma- terpene (13.39 %), propanal (29.43 %), 1 -Isopropylidene-3-N-butyl2-cyclobutene (6.52 %), and benzene methanol (8.36 %). The results of microbial count at the last day of storage showed that the treatment containing 20 % and 25 % nanoemulsions significantly delayed microbial spoilage compared to other treatments (p < /em><0.05). The control treatment also indicated the highest level of microbial spoilage; as represented in Log 6, the maximum bacterial count in chicken fillets and the shelf life of BHT at 0.02 % concentration continued until day 3. Furthermore, in organoleptic evaluation, 20 % and 25 % nanoemulsion treatment scored higher than other treatments. CONCLUSIONS: Nanoemulsions of Cuminum cyminum EO at concentrations of 20 % and 25 % were able to delay the microbial spoilage of chicken fillets and produced organoleptically favorable results.