This study aimed to identify the essential oil compound from Cinnamomum zeylanicum barks by using GC-MS analysis and evaluate essential oil inhibition effects against Listeria monocytogenes, Escherichia coli, Enterobacter aerogenes, Pseudomonas erogenous and Staphylococcus aureus by using agar diffusion method and studied kill-time for this bacterium. The yield of Cinnamomum zeylanicum essential oil was 5%. Cinnamaldehyde 57.83% was the main compound in the essential oil extract, followed by cyclohexane carboxylic acid 9.29% and 6-octadecenoic acid 8.41%. Gram-positive and Gram-negative bacteria were inhibited growth after addition 6, 12 and 18 μL of essential oil. Zone diameter of inhibition ranged from 17.00-30.30 mm for bacterial test. A concentration of 10, 20 and
30 μL.mL-1 of the essential oil caused a rapid and steady decline in the number of viable cells from 2 to 5 Log. cycles of all strains during 24 hours.