Using the potential of natural materials as special food additives for reducing the use of chemical preservatives in production of food stuff, considering their antiMICRObial properties, is of great importance. In this research, the in vitro antibacterial effects of Pelargonium graveolens essential oil on Staphylococcus aureus, Escherichia Coli, Salmonella enterica and Listeria monocytogenes were studied. To do so, 4ml of the essence was prepared using Clevenger. Afterward, MIC and MBC were determined. MIC of S. aureus and E. coli was equal to 62.5 ppm and this figure for S. enterica and L. monocytogenes was 125 and 31.25 ppm, respectively. The results showed that, comparing to gram-negative bacteria, the gram-positive bacteria were more sensitive to this essential oil. The most sensitive tested MICROorganisms were L. monocytogenes, S. aureus, E. coli, and S. enterica. Finally, we found that the use of some ornamental plants for inhibiting bacteria can be a helpful approach in future researches.