The nutritional implications of the presence of phytates in certain food products are described. Several techniques for phytate removal or conversion in foods are discussed, with special emphasis on enzymic conversion. The application of mould phytases for the dephosphorylation of phytate compounds is evaluated with respect to legume products, breadmaking, chicken diets and corn wet milling. The properties of different phytases are summarized and data concerning biosynthesis of phytate-degrading enzymes are also analysed.