This invention relates to a thermoplastic vulcanizate having excellent elongation comprising an isotactic polypropylene matrix phase in which a cross-linked ethylene-propylene-diene terpolymer (EPDM) is dispersed, the vulcanizate comprising the reaction product of:a) 35 to 55 wt % of an ethylene-propylene-diene terpolymer (EPDM);b) 10 to 40 wt % of isotactic polypropylene (iPP);c) 0.5 to 25 wt % of a propylene-ethylene-diene terpolymer (PEDM) compatibilizer, said compatibilizer having a heat of fusion of less than 2 J/g; andd) 0.015 to 0.03 wt % of curatives;wherein the percentages of components (a) to (d) are based on the total weight of the mixture.