In this research, the improvement of the impact strength of wood flourrecycled polypropylene (PP) composites through impact modification was studied. For this purpose, a virgin polypropylene (VPP) was thermomechanically degraded by five extrusions under controlled conditions in a twin-screw extruder at a rotor speed of 100 rpm and a temperature of 190 degrees C. PP (VPP and recycled PP at the second and fifth stages) and wood flour were compounded at 50 wt % wood flour loading in a counterrotating twin-screw extruder in the presence different contents of ethylene vinyl acetate (EVA) to produce the wood flourPP composites. From the results, the composites containing recycled PP exhibited significantly lower impact strengths. The addition of EVA up to 9 wt % increased the impact strengths of the composites made with PP recycled two and five times by about 63 and 41%, respectively. The composites containing VPP exhibited higher impact strengths than those containing recycled PP and EVA. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012