Objective: The present study examines the impact of cognitive computer games on working memory, attention and cognitive flexibility among students attention deficit/hyperactivity disorder (ADHD). Method: This study is a quasi-experimental (pretest, posttest control group design). In this study 20 students whom were recognized as ADHD based on Conner's questionnaire clinical interview, and CSI4 test, were chosen and after matching them based on IQ and educational development evaluation. Then, they were assigned as two experimental group (10 students) and control group (10 students). The data were analyzed by one-way ANOVA, Leavene test and Covariance. Results: The results showed a significant difference between the two groups in working memory, attention and cognitive flexibility. Conclusion: Cognitive computer games could improve working memory, attention and cognitive flexibility in students with ADHD. These games lead to the shortening of reaction time and the improvement of information analysis skills. They also increased mental flexibility, processing speed, working memory