This explores people’s relationship with their mobile phones and argues that it embodies an emotional attachment and mobile phone use involves emotional behaviours. The chapter describes those behaviours, both in the way that people are observed using their mobiles and, in the terms they use to describe their relationship with them. It offers evidence from recent empirical research of how attached people have become to their mobiles and it offers some explanations. Finally the chapter suggests some of the implications that these behaviours might have on the development of mobile communications and how these are different from that of any other information communication technology devices.