The aim of this study is to investigate the filling properties of an agricultural waste, olive pomace powder (OP), for polypropylene (PP) matrix material. Different weight fractions of OP (from 10 to 40 wt %), which has a median particle size of 21.36 mu m (D50) mu m, were loaded into PP by high-speed thermo kinetic mixer. In this research, the effects of weight fraction of OP within PP on mechanical, viscoelastic, thermal, chemical, crystallographic, and morphological properties of PP composites were investigated by tensile and three point bending test, dynamic mechanic analysis, thermogravimetric analysis and differential scanning calorimetry, Fourier transform infrared analysis, X-ray diffraction analysis, and scanning electron microscopy. When 40 wt% OP filler was loaded into PP, the Young's modulus and flexural modulus of PP increased by about 62.5% and 19%, respectively. The storage modulus and thermal stability of PP were remarkably enhanced with increasing OP weight fraction. (C) 2017 Elsevier Ltd. All rights reserved.