The crystalline structure and physico-mechanical properties of polypropylene (PP) blended with ethylene-propylene copolymer (EPM) were investigated. WAXS diffractograms showed that the addition of EPM did not affect the crystalline structure of PP. DSC curves revealed the presence of two T-g peaks indicating the amorphous phases of EPM and PP. As EPM increased, the elastomeric domains cavitated from PP matrix increased while the tensile stress and modulus of elasticity decreased. Impact strength, on the other hand, increased, and showed a remarkable effect at 30% EPM/PP. The properties of the blended polymers were compared with the commercial PP impact copolymer, and it was found that polyblends containing 30% EPM was suited for applications on products requiring very high impact strength. Further addition of EPM from 40 to 50% produced very high impact strength, but the tensile stress and modulus of elasticity were very low.