Biomaterials are specialized substances designed to interact with biological systems to diagnose, treat, improve, or replace any part of the human body, from tissue to complete organs or to improve a function. In medicine, nanocomposites are nanoscale materials that unite properties of one or more materials to maximize functionality, performance, and application areas. The synthesis of nanocomposites based on biomaterials is specific and straightforward while maintaining sustainability standards without damaging the compatibility with biological systems. Green biomaterials include bioinspired materials, renewable resources based on ceramics, natural fibers based on composites, biodegradable polymers, and materials obtained from agricultural waste. Their development and synthesis involve techniques such as precipitation, vapor phase deposition, electrochemical synthesis, and emulsions that allow maintaining control over the nanocomposite’s morphology, structure, and composition. Biomaterial-based nanocomposites have properties that can be “tuned” to meet specific requirements for each of the possible medical applications, such as mechanical strength, electrical conductivity, biodegradability, drug loading capacity, and cell binding capacity. This type of nanocomposites is suitable for treatments such as tissue medicine, controlled drug release, medical imaging, biosensors, and bone medicine. Nanocomposite biomaterials are currently used in controlled and targeted drug delivery systems, and they are prevalent in the manufacturing and development diagnostic devices such as biosensors and imaging agents. This chapter will discuss the synthesis and applicability of nanocomposite biomaterials, which represent a promising area of research due to the unique properties of biomaterials and their affinity with the human body.