Since the first superabsorbent polymer (SAP) was reported by the U. S. Department of Agriculture (1), SAP research and development has focused on its extraordinary high water absorbency and its applications. The most remarkable success has been in hygiene applications such as disposable diapers and sanitary napkins; over 80% of SAP is currently consumed in these applications. Because the SAP market in hygiene applications has been extremely competitive, SAP research and development have been greatly accelerated and have unveiled many unique properties of SAP other than high water absorbency. Many new applications have been investigated through such active research and development, and SAPs have already been used effectively in some new applications. As a result, their consumption has steadily increased year by year. Furthermore, there are still many potential applications under development. However, at the same time, the research and development showed that the most common SAPs, those of the poly(acrylic acid)-type, are not always suitable for new applications since they are especially designed for hygiene applications and are supplied in powder form. In order to fit the properties of SAP into the new applications, physical and chemical modifications are sometimes required. In this chapter, some new high performance superabsorbent polymers and their applications will be described.