This study investigated the psychosocial characteristics of children and adolescents who were addicted to internet. 1107 children and adolescents were administered several self-report inventories assessing internet addiction, internet expectancy, self-control, parent-adolescent communication, parent control of internet, peer relation, and loneliness. Results indicated that internet addicted adolescents had more expectancy for internet, less self-control, more dysfunctional communication with parents, and more withdrawn from peers than non-addicted. To determine relative contributions of these variables, multiple regression was conducted. It was demonstrated that internet expectancy, self-control, dysfunctional parentadolescent communication, and parent control of internet explained adolescent internet addiction.