Amino acids are the main form of nitrogen transported in the plant body, and the transport of amino acids across cellular and sub-cellular membranes is considered essential for nitrogen economy in plants. In particular, the long-distance transport of amino acids through the phloem and xylem, and the transfer of amino acids between the phloem and xylem during nitrogen cycling, requires both cellular importers and exporters. Even though some of the amino acid carrier proteins were identified more than 15 years ago, the physiological roles of many amino acid transporters are still unclear. There is even less known about the proteins that mediate the cellular efflux of amino acids. Recently, however, there have been reports of amino acid carrier proteins that can mediate both export and import, and might play roles in nitrogen cycling and other physiological processes. In this chapter, we will summarize what is known about plant amino acid exporters and their physiological roles.