The purpose of the research was to determine the antibacterial effects of the cinnamon (Cinnamomum zeylanicum) essential oil and hydrolate against Escherichia coli, Staphylococcus aureus, Listeria innocua and Pseudomonas aeruginosa. The antibacterial activity of the essential oil was determined by broth microdilution method. The antibacterial action of the hydrolate was determined by the broth microdilution method and by agar diffusion method. The minimal inhibitory concentration (MIC) was determined and confirmed by plate count method. For E. coli, the MIC value was 0.78 mg/ml, for S. aureus 0.2 mg/ml, for L. innocua from 0.1 to 0.2 mg/ml and for P aeruginosa 1.56 mg/ml. The best antibacterial activity was showed for L. innocua, which had the lowest MIC value. Cinnamon hydrolate showed no antibacterial activity irrespective used methodology. The results of experimental work showed that cinnamon essential oil has antibacterial properties and has a greater effect on gram-positive (S. aureus and L. innocua) then on gram-negative (E. coli, P. aeruginosa) bacteria. The results suggest that antibacterial effects of the cinnamon essential oil can lead to wider use of the cinnamon essential oil as a natural antibacterial agent in food.