Prebiotics are defined as non-digestible food ingredients, which beneficially impact the organism of a host by means of selectively stimulating the growth and/or activity of one type or of a limited number of colonic microbiota. There are 5 basic criteria for classifying food ingredients as prebiotics: resistance to digestion in upper gastrointestinal tracts; fermentation by intestinal microbiota; beneficial impact on health of host; selective stimulation of the growth of probiotics; stability under varying food processing conditions. Owing to their valuable technological properties, the prebiotics are applied in many food products as fat and sugar substitutes or as a texture- and gel-forming agent. In the paper discussed are the definitions, criteria of classification, profile of prebiotic substances, and their industrial applications.