Biomaterials are playing a key role in the frame for bioeconomy. They could replace fossil-based materials and make a positive contribution to the mitigation of climate change and the sustainable use of natural resources. This will require a better understanding of how the structure and functionality of the materials interrelate. In this context, this course relates with key topics on biomass valorization and natural polymers, including their origin, extraction/isolation, characterization, physiochemical, structural and biological properties. Their applications in key areas such as biomedicine, composites, agriculture, and environmental engineering are also discussed.