Without a doubt, petroleum-based resources have caused in increased interests in bio-renewable polymer-based, relatively cheap, readily available and environmentally friendly materials. These interests are growing in leaps and bounds and have and continue to elicit even greater interest in order to come up with new resources that are less unfavorable in terms of the environment, health and cost of production. This quest has led to exploration of producing composites and nanocomposites, especially, those with polymer substrates for use in various applications, including: automotive, aerospace, electronics, civil, medical and biomedical, drug delivery, sensors and actuators and many other fields of human endeavors. In this regard, noble metal nanoparticles (NPs) are intensively used for medical specialty applications like drug delivery and tissue engineering. This is because of their very unique and exceptional physicochemical and optoelectronic properties. In this chapter, the focus will mainly be based on the various techniques for green biosynthesis of composites and nanocomposites, specifically, for applications in medical and biomedical fields. Very briefly, mention will be made in other fields of application.