The morphology of the thermoplastic vulcanizates prepared from ethylene-propylene-diene terpolymer, polypropylene and high density polyethylene(HDPE) or ethylene based ionomer were studied. Blends were prepared in a laboratory internal mixer where EPDM was cured in the presence of PP and HDPE or ionomer under shear with dicumyl peroxide(DCP). The effects of DCP concentration and rubber/plastics composition were studied. In the morphological analysis by scanning electron microscopy (SEM), a small amount of EPDM acted as a compatibilizer to HDPE and PP. It was also revealed that the dynamic vulcanization process could reduce the domain size of the crosslinked EPDM phase. When ionomer was added to EPDM/PP blend, the thermoplastic vulcanizate showed typical ductile fracture topology and the trend was more clearly observed when DCP contents and ionomer contents are higher.