Purpose: The purpose of this study was to confirm whether the Swiss Ball exercise program is effective to improve lower extremity function and activity of daily living of elderly women with mild cognitive impairment (MCI). Methods: This study was a double blind control study. Subjects participated 34 female elderly women who were assigned to exercise group (n=17) and control group (n=17). The Swiss Ball exercise program was performed 2 times a week during the 12 weeks. Pre-and post-exercise various measurements were made: lower extremity function (OLS, TUG, STS). Results: In exercise group, There showed statically significance improve between pre-and post-exercise in OLS (7.29${pm}$1.10 and 7.64${pm}$1.32), TUG (10.47${pm}$2.03 and 10.05${pm}$2.04), STS (7.71${pm}$1.04 and 7.94${pm}$.82)(p<.05). ADL also showed statically significance improve between pre-and post-exercise (13.76${pm}$3.54 and 12.82${pm}$3.39, p<.05). There showed statically significance difference between two groups (p<.05). Conclusion: The Swiss Ball exercise program improved lower extremity function and ADL of elderly women with MCI. Further studies are required to examine the significance of the assessment of motor function of lower extremities.