Ubiquitous commerce, also referred to as “u-commerce” or “über-commerce”, is the combination of electronic, wireless/mobile, television, voice, and silent commerce. It extends traditional commerce (geographic, electronic, and mobile) to a world of ubiquitous networks and universal devices. This chapter introduces the basic ideas and characteristics underlying the concept of u-commerce. It discusses market drivers and applications of u-commerce as well as the underlying technology of u-commerce. It highlights the benefits and challenges of u-commerce and provides specific research directions for future research.