Dietary carbohydrate are classified according to their degree of polymerization into sugars, oligosaccharides, and polysaccharides, the latter consisting of starches with different degrees of resistant to complete digestion and of nonstarch polysaccharides. The composition of dietary carbohydrates ingested throughout the pigs' lifespan varies widely. This chapter provides an overview of the carbohydrates present in the diet for pigs and how the carbohydrates are digested, absorbed, and utilized. The primarily chemical classification is by composition of sugar monomers, the type of linkage and molecular size. Lactic acid appears in the portal vein in the early phase of absorption and is better synchronized with the absorption profile of starch than with short-chain fatty acids (SCFA). The site of absorption of carbohydrate-derived products influences the utilization of energy. From the fermentation equation for the conversion of carbohydrates into SCFA, it can be estimated that approximately 25% of the energy is lost in H 2 and CH 4 .