Polypropylene-based compounds are increasingly attractive because of low cost, processability, and good balance of properties. In recent years, metallocene ethylene-octene copolymers have started displacing EPR and EPDM as an impact modifier for PP. This study examines the effect of compounding conditions and composition on the properties of talc/ethylene-octene copolymer/PP compounds. The mechanical properties of the compounds were not significantly affected by the mixing conditions on a laboratory twin screw extruder. The use of 30 wt% of talc provided a twofold increase in tensile modulus compared with pure PP. Impact resistance of filled and unfilled compounds was found to increase rapidly once the copolymer concentration reached around 20 wt% based on the polymer phase. Modulus and tensile strength decreased linearly with copolymer concentration. Four different commercial maleic anhydride-grafted PPs were tested as interfacial modifiers. In the best cases, a slight tensile strength increase was observed when using between 2 and 10 wt% of modified PP.