Hydrogels are polymeric networks with three-dimensional configurations capable of imbibing high amounts of water or biological fluids. The application of hydrogels technology is being widely used in the pharmaceutical industry as drug delivery systems. In this book, the authors present current research in the study of the synthesis, characterisation and applications of hydrogels. Topics include the synthesis of protein-based hydrogels for biomedical applications; the role of hydrogels in the development of artificial bone substitutes; protein-based hydrogels from fish industrialisation wastes; silk fibroin hydrogels; PVP-Based hydrogels; and the tribological properties of polyvinyl alcohol hydrogels as artificial articular cartilage.