Many modern materials and structures are the result of inspiration drawn from nature. The field of biomimetics has formalised this relationship, and accelerated the rate at which concepts from nature may be adopted, adapted and utilised within development of new materials, textures and forms. At the same time, many researchers are seeking to generate materials from renewable or bio-based materials. This chapter looks in greater detail at the natural materials introduced in chapter three to consider these two aspects. Examples demonstrate how the composite nature of natural materials such as bone or plant cell walls lead to enhanced mechanical performance and toughness. Key principles including composite mechanics and crack arresting properties; self-assembly and hierarchy within the material structure are discussed. Other examples demonstrate how the improved understanding of natural materials has led to advances in diverse fields such as promoting or inhibiting adhesion, in creating buildings and structures or in generating motion. At a time when the suite of materials which claim to be bio-based or bio-inspired appears to increase almost exponentially, selected examples are presented to brief the reader on key advances, and likely future developments. While the chapter is not exhaustive, it aims to show the breadth of application for bio-inspiration when applied to development of bio-based materials.