Among the 12 principles that define green chemistry, the use of renewable resources is of paramount importance in the perspective of building a sustainable society. The effort that has been put, in the past 25 years, into the research and development of new materials with controlled nanoscale structures and properties has not specifically taken into account the possibility of employing natural resources. This trend has, nevertheless, changed in the past 10 years. In this chapter, some examples of nanomaterials and nanoscale-related processes are overviewed through the prism of sustainability. In particular, it will be shown how natural resources, from proteins to carbohydrates and more complex organisms, can be employed as precursors in the synthesis of nanomaterials.