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, characterization 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 industrialization wastes; silk fibroin hydrogels; PVP-Based hydrogels; and the tribological properties of polyvinyl alcohol hydrogels as artifical articular cartilage.