The Information and Communication Technologies (ICT) generate new styles of meeting people or connecting with friends or strangers. In this context, the internet and the mobile phone deserve special attention. This article deals with the maladaptive use of these technologies. By reviewing the literature published between 1991 and 2005 and indexed in the databases of PsycINFO, Medline, Psicodoc, IME, and ISOC, we aim to determine whether maladaptive use of these technologies can be considered a mental disorder, and if so, of which type. We describe the psychological phenomena of maladaptive use of the internet and mobile phones, we review research on prevalence and possible risk groups, and finally we discuss some of the criticisms made with regard to the existence and classification of this disorder. It is concluded that excessive use of the internet can lead to a mental disorder of the addictive type, which can particularly affect individuals with special emotional needs, as well as adolescents and young adults. Among specific applications of the internet, a major risk is found for the use of communicative and synchronic applications, such as chats and online role games, since they permit hyperpersonal communication, playing with different identities, and projections and dissociation without consequences in real life. Furthermore, the internet can play an important role in the development and maintenance of other addictions, such as pathological gambling and sex addiction. In contrast to the case of the internet, maladaptive use of mobile phones may be considered abuse, but not addiction, since their use does not lead to the rapid emotional changes or the playing with identities that can take place in chats and online role games.