In this study, synthesis and polymerization of epoxidized methacrylated castor oil (EMETCO) is demonstrated. EMETCO is synthesized in two steps. Castor oil (CO) is methacrylated with methacryloyl chloride at the first step. Then the methacrylated castor oil (METCO) is epoxidized by Prilezhaev reaction. Structure of EMETCO is determined by H-1 NMR and IR techniques. EMETCO was copolymerized with acrylic acid (AA), styrene (ST), and methacrylic acid (MA). Thermal and mechanical properties of the synthesized polymers are evaluated. Among the polymers synthesized EMETCO-ST-MA polymer gives the highest storage modulus at 2.25 GPa. On the other hand, EMETCO-AA copolymer exhibited the lowest storage modulus at 350 MPa. Moreover, EMETCO-ST copolymer shows the lowest 5% weight loss temperature while EMETCO-MA exhibited the highest 5% weight loss temperature at 280 degrees C. Practical Applications: Epoxidized Methacrylated Castor Oil is a bio-based epoxy acrylate monomer. The low viscosity and two different functional groups make this material suitable for many polymerization reactions and applications. This compound would be used as a replacement materials for many industrial monomers such as styrene, acrylated epoxidized soybean oil, or prepolymers in the future. EMETCO is a castor oil based epoxy acrylate monomer. It is a hybrid material that contains different types of polymerizable groups. Synthesis of the monomer is not complicated and completed in two steps. Methacrylation of castor oil occurs at the first step and epoxidation follows that reaction. The resultant compounds is a transparent oil.