Abstract: Fructooligosaccharides (FOS) are prebiotic compounds used in the food, cosmetic and dentistry industries. These value-added compounds have been subject to attention and research for the last decade because of the health-promoting properties related to a regular FOS intake. FOS are natural carbohydrate compounds formed by several fructosyl units linked by a β-(2-1) linkage to terminal glucose. FOS are naturally occurring in some fruits, vegetables and other crops but, due to seasonal dependence and industry demand, several efforts have been made to produce FOS biotechnologically, either using whole cells of microorganisms that possess transfructosylation enzymes which catalyze FOS synthesis or systems with purified enzymes that look to improve FOS production yields. FOS structure, occurrence in plants, health properties, production, purification and developments are reviewed and discussed in the chapter.