Soybean oil and jatropha oil have high contents of unsaturated fatty acids which can be converted to epoxy fatty acids. The vegetable oil-based epoxy materials are sustainable, renewable and biodegradable materials replacing petrochemical-based epoxy materials in some applications. To produce epoxidized soybean oil (ESO) and epoxidized jatropha oil (EJO), the epoxidation was carried out by conventional chemistry at 50 o C and atmospheric pressure for about 10 h. The maximum reaction conversion was 83.3% for the epoxidation of soybean oil and 87.4% for the epoxidation of jatropha oil. An excess amount of hydrogen peroxide was necessary in the reaction to achieve high reaction conversion. A possibly undesirable side reaction was reaction of the epoxy ring opening resulting in hydroxy functional groups observed by Fourier Transform Infrared Spectroscopy (FTIR). The highest epoxy content of ESO produced had 6.13% (wt), which is comparable to the commercially available ESO. The highest epoxy content of EJO produced was 4.75% (wt); however, there is no commercially available EJO to make a comparison. This project hopes to help Thailand to start producing vegetable oil-based epoxy ourselves. Moreover, it could give an alternative market to jatropha oil farmers.