Blends of zinc oxide-neutralized maleated EPDM terpolymer, (m-EPDM) and zinc salt of an ethylene-methacrylic acid copolymer, (Zn-EMA), wherein Zn-EMA does not exceed 50% by weight, behave as an ionic thermoplastic elastomer. A typical 60/40 m-EPDM/Zn-EMA blend has the following properties : 100% modulus, 5.53 MPa; tensile strength, 12.10 MPa; elongation at break, 220%; and tension set at 100% elongation, 29%. Properties of the blends are greater than those predicted by the additivity rule. Dynamic mechanical and infrared spectroscopic studies revealed that the ionic bonds are formed at the interfaces of m-EPDM and Zn-EMA, which facilitates formation oi the technologically compatible blend.