Antioxidative and antimicrobial activities of essential oils of cassia (Cinnamomum cassia) and dill (Anethum graveolens L.) were investigated. Essential oils used in this study were added to soybean oil and stored at $65^{circ}C$ for 9 days to examine their antioxidant activities using peroxide value (POV). The results showed that dill essential oil possessed a higher antioxidant activity than cassia essential oil. Strong antimicrobial activity was observed in cassia essential oil, whereas low activity was observed in dill essential oil against the test microorganisms. Heat stability and cell growth inhibitions were investigated with different concentrations of cassia oil. Results showed that cassia oil had thermal stability in a wide range of $70-160^{circ}C$. Cassia inhibited cell growth of Bacillus cereus KCTC 1022, Micrococcus luteus A TCC 9341 and Escherichia coli ATCC 25922, but not great on Salmonella typhimurium ATCC 14028 at level of 200 ppm. In conclusion, the results indicate that dill essential oil could be a potential candidate for an antioxidative agent, while cassia essential oil could be suitable for use as an antimicrobial agent in the food industry.