The dynamic mechanical studies, impact resistance, and scanning electron microscopic studies of ethylene propylene diene terpolymer-poly(vinyl chloride) (EPDM-PVC) and methyl methacrylate grafted EPDM rubber (MMA-g-EPDM)-PVC (graft contents of 4, 13, 21, and 32%) blends were undertaken. All the regions of viscoelasticity were present in the E＇ curve, while the E " curve showed two glass transition temperatures for EPDM-PVC and MMA-g-EPDM-PVC blends, and the T-g increased with increasing graft content, indicating the incompatibility of these blends. The tan delta curve showed three dispersion regions for all blends arising from the alpha, beta, and Gamma transitions of the molecules. The sharp alpha transition peak shifted to higher temperatures with increasing concentration of the graft copolymer in the blends. EPDM showed less improvement while a sixfold increase in impact strength was noticed with the grafted EPDM. The scanning electron microscopy micrographs of EPDM-PVC showed less interaction between the phases in comparison to MMA-g-EPDM-PVC blends.