This chapter reviews the processes developed to produce oat-based functional food ingredients, with special emphasis on those with enhanced health benefits. The processes discussed in this chapter have been divided into six groups based upon the fractionation methodology utilized. The first five, involving soluble fibre, are dry-milling operations, organic-solvent extractions, aqueous extractions, enzyme processes, and extraction methods utilizing acid/base conditions or temperature. The last is for cellulosic-based oat fibres. In addition to the process descriptions, information is provided on the functionality and applications of the end products.