Melt blends of isotactic polypropylene with ethylene(50)-propylene(50) random copolymer have been studied. Measurements included rheological properties from a capillary rheometer and RDS, thermal properties from differential scanning calorimetry. and mechanical properties from Instron. Morphology was determined from cryogenically fractured surfaces of injection molded tensile specimen using a scanning electron microscopy. With an emphasis on rheology measurement, this paper considers the effects of composition ratio and melt property on the microstructure, mechanical and thermal properties of the blends.