Purpose: This research aimed to study the effect of 8 weeks core stability training on static balance of the children with Down syndrome. Methods: A total of 16 children with Down syndrome from rehabilitation center of Noor Abad City were selected and randomly divided into 2 groups of control (n=8) and experimental (n=8). At the pretest and posttest, subjects’ static balances were evaluated by modified stork stand test. The training program was conducted in 8 weeks, 3 times a week, and each session lasted 45-60 minutes. Statistical analysis was done by dependent and independent t-test using SPSS version 21 (P≤0.05). Results: Our results indicated a 67% progress in static balance (3.64 s) in the experimental group (P=0.0001) and their 84% superiority (4.14 s) over the control group in the post-test (P=0.0001). Conclusion: According to these results, core stability training improves the static balance of the children with Down syndrome and can be used in their rehabilitation program.