Abstract: The objective of this research was to analyze the capability of cinnamon essential oil as antibacterial agent which is further applied as natural food preservative agent in food products. The cinnamon essential oil was obtained by using steam distillation. Furthermore, the water based microemulsion of cinnamon essential oil was developed by using several types of emulsifiers. In this investigation, four different emulsifiers were tested, namely Tween 20, 80, soya lechitin and Carboxymethyl Cellulose (CMC) to stabilize the essential oil in water. The emulsifiers were used at 2% w/w while the essential oil concentrations were varied at 0.5, 1 and 1.5%. Moreover, the microemulsion produced here was tested for particle size, storage stability, antibacterial activity and sensory evaluation once it is incorporated as preservative for Indonesian beef meat balls. The droplet sizes of the cinnamon essential oil microemulsion were found to range from 30-100 nm and after one week of storage at room temperature, the microemulsion solution did not undergo changes in droplet size which showed the emulsion stability during storage. The antibacterial activity of cinnamon essential oil showed satisfactory results toward food borne bacteria, namely Staphylococcus aureus and Escherichia coli. The results were measured from the zone of inhibition diameter formed by the microemulsion solution. Among the four types of emulsifier, CMC (Carboxy-Methyl-Cellulose) showed the best results as an emulsifying agent. Furthermore, in this study the micro emulsion was applied as a food preservative agent for meatball, known locally as the beef bakso. CMC and cinnamon essential oil (0.5, 1 and 1.5%) showed satisfactory results in delaying the spoilage of the meatballs. Among the four types of emulsifier, CMC showed the best emulsifying agent in terms of antibacterial activity. After the microemulsion solution was applied to meatballs. CMC and cinnamon essential oil (0.5, 1 and 1.5%) showed satisfactory results in delaying the spoilage of the meatballs. From the sensory evaluation, the overall acceptance from meatball with addition of CMC and essential oil were higher compared to meatball without treatment.