In recent years, there has been a growing need for innovations in nano-biomaterials that promote the substitution, repair, or recovery of fractured bones to improve the quality of life. Materials such as ceramics, polymers, carbon-based materials, calcium phosphate (CP) based nanomaterials, and their composites for bone implant applications. However, they show various drawbacks such as toxicity, low mechanical stability and complexity in processing, low osteointegration, and lack of antimicrobial abilities. Substitution of minerals or reinforcement of carbon-based materials is one way to modify the properties of CP-based materials. Multifunctional materials like nanofiller, nanofiber, carbon nanotubes, graphene oxide, and metal oxides can be reinforced/encapsulated with CP-based materials to overcome the shortfalls. This chapter briefly discusses the variety of nano-bioimplant materials, their case studies on the mechanical properties, corrosion behavior, and in vitro and in vivo biological behavior for their application as load-bearing bone implants. © 2025 Elsevier B.V., All rights reserved.