Dietary carbohydrates constitute a major fraction of the diets for pigs. The carbohydrate fraction consists of mono-, di- and oligosaccharides and two broad classes of polysaccharides – starch and non-starch polysaccharides (NSP). The carbohydrate fraction has a diverse composition in terms of constituent sugars (pentoses, hexoses, deoxysugars, etc.), glycosidic linkages (alfa or beta), size (degree of polymerisation from one to several thousand), and physical form (soluble in water, insoluble, cation and adsorbing properties). It is now evidential clear that the composition of the carbohydrate fraction influences the digestion and absorption processes of carbohydrates and other nutrients in the various parts of the gastrointestinal tract, it has a profound influence on the secretory response of the gut to feed intake, the volume flow, the mucosal architecture, the composition of the gut flora and the development of the gastrointestinal tract.