Thermal and morphological studies have been performed on polymer blends based on ethylene-octene copolymer (PEE)/PP and ethylene-propylene-diene copolymer (EPDM)/PP. The thermal and morphological behavior of PEE, EPDM, PEE/ PP, and EPDM/PP systems were analyzed by differential scanning calorimetry (DSC) and polarizing light microscopy, respectively. It was observed that the behaviors of crystallization kinetics of PEE/PP and EPDM/PP blends were similar. It was also observed that addition up to 10-20% (w/w) of elastomers resulted in increasing of spherulite size. The heat of fusion (DeltaH(f)) and crystallinity degree of PEE/PP and EPDM/PP systems decreased when the elastomer contents were increased.