We report the case of a 10 year old patient diagnosed with attention deficit hyperactivity disorder (ADHD) and comorbid video game addiction, who was treated with medication combined with a novel cognitive training method based on video games called TCT method. A great risk of developing video game or internet addiction has been reported in children, especially in children with ADHD. Despite this risk, we hypothesize that the good use of these new technologies might be useful to develop new methods of cognitive training. The cognitive areas in which a greater improvement was observed through the use of video games were visuospatial working memory and fine motor skills. TCT method is a cognitive training method that enhances cognitive skills such as attention, working memory, processing speed, calculation ability, reasoning, and visuomotor coordination. The purpose of reviewing this case is to highlight that regular cognitive computerized training in ADHD patients may improve some of their cognitive symptoms and might be helpful for treating video game addiction.