EPDM/organophilic clay composite have been prepared by direct melt mixing in banbury mixer. XRD show a insertion of polymer chains in the interlayer of organophilic clay, whereas no insertion occurs in samples prepared from an unfuctionalized clay and EPDM. The dynamic-mechanical analysis indicates that compatiblity between the polymer matrix and organophilic clay result an increase in the pleateau modulus, and the glass transition temperature(Tg) with respect to the corresponding values of samples prepared from an unfunctionalized clay. The results indicated that organophilic clay(Cl5A) could be dispersed in EPDM matrix more uniformly than unfunctionalized clay(Na(+)-MMT) and resulting EPDM/organophilic clay(Cl5A) hybrids show excellent tear resistance and tensile strength compared with unfilled EPDM and EPDM/Na(+)-MMT composites.