Modified polypropylene was prepared by blending with potassium titanate whisker (PTW) and 10 w/w% talc via Haake extruder followed by injection molding. Reinforced with both PTW and talc, the PP composites exhibited better mechanical properties. The tensile modulus and flexural modulus of PP composites tend to increase with the increasing of whisker concentrations. The talc plays a synergistic role in improving the mechanical properties of composites and reducing cost. Torque measurement shows the PP composites has a good processing condition due to lubrication of PTW. TGA test shows PP composites containing 20 w/w% PTW and 10 talc is useful for improving PP composite's thermo oxidative stability. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3455-3459,2010