||A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent leakage within the joined objects while under compression. Fluorine rubber (FKM), which has the excellent physical properties and the high reliability, was mainly used as a fuel cell gasket material. Recently, EPDM rubber emerged as an alternative material to FKM rubber. Which is used due to its good injection moldability and the low production cost compared to FKM. But several issues are still remained to apply practically, because EPDM rubber has the poor thermal properties in the harsh conditions. Thus, it is necessary to develop the new EPDM rubber material capable of thin film injection molding and maintaining the elasticity at high temperature for a long period. In this study, we examined to find the optimizing composition with carbon black, nano-clay, anti-oxidant and talc as fillers and DCP and TAIC as cross-linking agents for EPDM gasket in fuel cells.