Background: This study compared the acute effects of aerobic (AE) and resistance (RE) exercise on reaction time (RT) and working memory (WM) in individuals with intellectual disability. Methods: RT tests and Corsi test for WM were performed before and after three intervention sessions: AE, RE, or control session consisting on watching video. Results: The RT values decreased significantly (p < 0.001) after both of AE and RE with higher extend after the RE but did not vary following the control session. Corsi scores increased significantly (p < 0.001) after AE but not after RE or control session. Conclusions: These findings suggest that the effects of acute exercise on cognitive function in individuals with intellectual disability depend on the exercise mode as well as the nature of the cognitive task. The RE seems to be more recommended for RT enhancement whereas only the aerobic one could improve WM in these individuals.