There are five basic taste qualities, umami, sweet, bitter, salty and sour tastes. These taste qualities are transduced through corresponding taste receptors that reside on taste cells in the oral cavity. Unlike salty or sour receptors, receptors for umami, sweet and bitter belong to G protein coupled receptor family. Recently, it has become apparent that taste receptors are localized in various cells and tissues other than those in the oral cavity, which similarly function for taste transduction. In this review, we will discuss expression and function of these taste receptors based on knowledge accumulated.