Objectives: This study aimed to analyze the constituents of essential oil of the aerial parts of lemongrass (Cymbopogon citratus) and evaluate its minimum inhibitory concentration (MIC) against five food-borne microorganisms (Bacillus subtilis, Staphylococcus aureus, Salmonella typhimurium, Vibrio cholera and Escherichia coli). Methodologies: The essential oil of lemongrass was obtained by hydro distillation. Its chemical constituents were analyzed with gas chromatography/mass spectrometry (GC/MS). Its MIC against the tested microorganisms was determined with macro dilution method. Results: The study showed that essential oil of lemongrass consisted of 40 components, with geranial (45.058%) and neral (33.100%) as major constituents. The MIC of essential oil of lemongrass against B. subtilis and S. aureuswas 31.25 μg/mL and 125 μg/mL, respectively. Somehow it was inactive against S. typhimurium, V. cholera, and E. coli. Conclusions: The essential oil of lemongrass was mainlyconsisted of neral and geranial. These two aldehydes compounds were responsible for moderate to strong antimicrobial activity of essential oil of lemongrass against B. subtilis and S. aureus.