Objective: A mentally retarded child is characterized by a delay in achieving movement characteristics and weakness in sensory-motor and cognitive performance along with noteworthy limitations in intellectual performance and adaptive behavior. Among the important problems of mentally retarded children compared to normal children is weakness in executive functions such as working memory, attention, response inhibition and cognitive flexibility. The purpose of this research is to investigate the effect of selected soccer exercises on sustained attention and cognitive flexibility of mentally retarded children. Methodology: The current research was a semi-experimental type that was conducted as a pre-test and post-test with a control group. 20 educable mentally retarded boys from Hamedan city who had an intelligent quotient of less than 70 were purposefully selected to participate in the research and were placed in two experimental and control groups of 10 people. The participants of the experimental group took part in the selected soccer training program for three sessions of 60 minutes per week for 12 weeks. Continuous performance computer test was used to measure children's sustained attention and Wisconsin card sorting test was used to measure their cognitive flexibility. In order to analyze the research data, statistical analysis of covariance and independent and dependent t-tests were used. Results: The results showed that 12 weeks of selected soccer training has a significant effect on improving sustained attention and cognitive flexibility of children with mental disabilities. Conclusion: According to the results of the research, it is suggested that mentally retarded children participate in soccer training so that they can increase their stable attention functions and cognitive flexibility.