In this study, a new type of bifunctional monomer from castor oil was investigated and the properties of the polymers that were obtained from this monomer were also evaluated and compared with the polymers that were obtained from acrylated epoxidized soybean oil (AESO). Castor oil (CO), first, was reacted with acryloyl chloride in order to obtain acrylated castor oil (ACO). Epoxidized acrylated castor oil (EACO) was obtained after the epoxidation reaction. EACO was characterized by H-1 NMR and IR techniques. Viscosity of the monomer was also determined. The viscosity of EACO was found as 1950 centipoise by using Brookfield type viscometer at 20 degrees C. After characterization, homo and block copolymers of the EACO with methyl methacrylate (MMA) and acrylic acid (AA) were synthesized by conventional radical polymerization techniques. Transparent and tough polymers were obtained after polymerization reactions. Thermal and mechanical properties of the polymers synthesized were also evaluated. EACO-AA (85-15%) copolymer showed 0.7 GPa storage modulus while AESO-AA (85-15%) copolymer showed only 0.37 GPa modulus. When compared 5% weight loss temperatures as a thermal stability indicator, it was observed at 332 degrees C for AECO-AA copolymer and 295 degrees C for AESO-AA copolymer.