This book deals with the preparation and characterization of several ZnO-reinforced bionanocomposites. Four different biocompatible thermoplastics were selected as matrix materials: high-performance poly(ether ether ketone) (PEEK), engineering poly(phenylene sulphide) (PPS) and commodity poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), each of them with different properties and end-use applications. The different chapters describe in detail the influence of the concentration and surface modification of the nanoparticles on the morphology, thermal, mechanical, tribological and antibacterial properties of each of the nanocomposite systems, analyzing their potential for specific applications like orthopaedic implants, minimally invasive surgical (MIS) products or food packaging materials.