: Attention deficit / hyperactivity disorder is one of the most common neuro-psychiatric disorders which started in childhood and continues into adulthood and causes problems in various aspects of life such as; personal, social, professional life, executive functioning, including working memory and concentration.Several studies regarding the treatment of this disorder have been proposed by the authors; current study formed due to lack of studies about effectiveness of neurofeedback with computer-based cognitive tasks on reducing symptoms of ADHD in Iranian adults.The study's aim was to evaluate effectiveness of neurofeedback with computer-based cognitive tasks on reducing symptoms of ADHD in adults.

Method: The research design was quasi-experimental with pretest-posttest and control group. The study population included adults with attention deficit/hyperactivity disorder that referred to Atieh clinic in Tehran. Among the statistical population, 8 patients in 2 groups, one experimental group and one control group of patients was selected based on convenience sampling method. The research instruments were the Beck Anxiety Inventory, Beck Depression Inventory, and Inventory adult attention deficit / hyperactivity disorder of Barkley, IVA test and CNSVS test. Data were analyzed by SPSS software and U Mann-Whitney. The independent t-test, Wilcoxon and Kruskal-Wallis test was also used for complementary results.

Results: The result showed that neurofeedback resulted is significant in reduction in of attention deficit and hyperactivity symptoms in the experimental group compared with the control group.

Conclusion: According to results, neurofeedback with computer-based cognitive tasks can reduce symptoms of ADHD in adults.