In the current research the effect of ZnO nanoparticles on the structure and properties of common thermoplastic polymers (polyoxymethylene (POM), polypropylene (PP), ethylene--octene copolymers (EOC)) and their binary blends is investigated. EOC content in the composites varies from 0 to 50 wt. %. The amount of nanostructured ZnO filler in the composites is changed in the interval from 0 to 5 wt. %. Tensile and frictional properties of ZnO modified nanocomposites are investigated. Results of the investigation show that ZnO additions cause increment in stiffness and strength as well as coefficient of friction of the investigated nanocomposites. The effect of ZnO modifier is the highest at low EOC content. The effect of ZnO is strongly dependent on the compatibility and crystallinity of the investigated nanocomposites.