AbstractPolysaccharides are ideal candidates for drug delivery and biomedical applications as they are easily obtained from natural sources. Furthermore, they can be subjected to a wide range of chemical and enzymatic reactions, they have biocompatible and biodegradable properties and have inherently low immunogenicity. Polysaccharides are potentially the materials of choice for the development of “smart” delivery systems, which are capable of releasing, at the appropriate time and site of action, an encapsulated drug. This Review examines various aspects of the crosslinking of polysaccharides, either for a single polysaccharide or mixtures, and also natural–synthetic hybrids. The Review focuses on the strategies for using these biodegradable polymers for controlled drug delivery, and examines in particular polysaccharide–drug conjugates, the encapsulation of drugs in hydrogels and aerogels, and the self‐assembly of polysaccharide drug‐loaded nanoparticles.