Purpose : The purpose of this study was to investigate the effects of core exercise on the static balance for females in their twenties. Methods : The core exercise program was conducted 3 times per week for 4 weeks. The result is based on the analysis of measuring static balance before and after the core exercise program. By using the GOOD BALANCE system, the assessment of the static balance ability was made before and after the exercise of 6 postures: normal standing, one left leg?and one right leg standing with eyes open and closed respectively. For each case, the experimental data were obtained in 3 items: mean X speed, mean Y speed, and velocity moment. Statistical analysis was performed using SPSS/Win(10.0) version and Willcoxon signed rank test. Results : From the result of this study, we found that mean X speed, mean Y speed and velocity moment of total postures significantly increased after the 4 week program of core exercises. Conclusion : These finding indicate that core exercises could be beneficial to females in their twenties due to the effect of increasing static balance.