Children's and adolescent's use of computer games and videogames is becoming highly popular and has increased dramatically over the last decade. There is growing evidence of high prevalence of addiction to computer games and videogames among children, which is causing concern because of its harmful consequences. There is also emerging evidence of an association between computer game and videogame addiction and attention deficit/hyperactivity disorder (ADHD). This is indicated by the occurrence of gaming addiction as a co-morbid disorder of ADHD, common physiological and pharmacological mechanisms, and potential genetic association between the two disorders. A proper understanding of the psychological and neurotransmitter mechanisms underlying both disorders is important for appropriate diagnostic classification of both disorders. Furthermore, it is important for development of potential pharmacological treatment of both disorders. Relatively few studies have investigated the common mechanisms for both disorders. This paper reviews new findings, trends, and developments in the field. The paper is based on a literature search, in Medline and PUBMED, using the keywords addictive gaming and ADHD, of articles published between 2000 and 2012.