The purpose of this study was to examine the effects of a physical activity program on body composition, depression and risk factors of dementia in elderly women. Subjects were 40 women aged 65~75 years, classified into two groups (experiment group 20, control group 20). The factors measured in this study were body composition (weight, percent body fat, body mass index, body fluid), depression (BDI score) and risk factors of dementia (K-MMSE, LDL-C, HDL-C, insulin, ${eta}$-amyloid, DHEAs) at 12 and 24 weeks before and after the program. Subjects of experiment group participated in a 24 week physical activity program (45~60 min, 3~4 day per weeks). Data were analyzed by repeated ANOVA method of SPSS, with accepting levels for all significances above ${alpha}$=0.05. The results of this study were as follows. In body composition, the experiment group showed significant differences in the weight, percent body fat and body mass index compared to the control group. In depression score, the experiment group showed no significant differences regarding BDI score level compared to the control group. In risk factors for dementia, the experiment group showed significant differences in levels of K-MMSE, LDL-C, HDL-C, insulin, ${eta}$-amyloid, and DHEAs compared to the control group. This study showed that a 24 week physical activity program had positive effects on almost all of the factors evaluated in elderly women, and that elderly women who did not participate in the program experiences no such positive effects. Therefore, regular participation in a physical activity program could be advocated as one strategy to enhance body fat, depression, and risk factors of dementia and may result in improving risk for diseases of age in elderly women.