Wood polymer composites (WPC) are widely used materials in different industries because of many application, processing and recycling advantages compared to traditional thermoplastic polymer composites containing mineral fillers [1]. However, the commercial success of these materials primarily depends on improvements in moisture performance, and ability to use recycled and waste material as a wood filler. The research regarding WPC is focused on the chemical interaction between dissimilar material components with an aim to provide strong adhesion to the surface of wood filler-polymer matrix [2]. The goal of this paper was to present results of investigations of exploitation properties of composites containing different plywood production industry byproducts and polypropylene. It was shown that modification of all composites with coupling agent maleated polypropylene (MAPP) considerably improve physical mechanical properties (tensile, flexural, impact strength) of WPC. MAPP (5 wt.%) additions also significantly improve water resistance of WPC. SEM investigations confirmed positive action of interfacial modifiers on strengthening of adhesion interaction between components wood and PP matrix that give considerable increase of exploitation properties of the WPC.