Non-digestible oligosaccharides (NDOs) are low molecular weight carbohydrates of intermediate in nature between simple sugars and polysaccharides. They can be obtained by direct extraction from natural sources, or produced by chemical processes hydrolyzing polysaccharides, or by enzymatic and chemical synthesis from disaccharides. The NDOs possess important physicochemical and physiological properties, and are claimed to behave as dietary fibers and prebiotics. Enrichment of diet with NDOs gives opportunity for improving of gut microecology including bacterial populations, biochemical profiles and physiological effects. Therefore, their industrial applications have rapidly increased in the last few years, both in prebiotic formulations and in symbiotic products (containing probiotic organism and prebiotic oligosaccharide).