Purpose: The purpose of this study was to investigate the effect of supplemental vitamin D on the physiological indices, muscle mass, and physical functions of aged women. Methods: A non-equivalent pretest-posttest design was used. The participants were 65 elderly women with low serum vitamin D levels. This study was conducted for 12 weeks. The experimental group (n=34) received vitamin D and regular exercise whereas the control group (n=31) received only regular exercise. The data were analyzed by the IBM PASW Statistics (SPSS) 19.0 program. Results: Serum vitamin D (U=0.00, p<.001), parathyroid hormone (U=99.50, p<.001) and calcium (U=250.50, p<.001) levels were significantly increased in the experimental group after the intervention. The experimental group showed significantly increased scores of muscle mass, strength, physical balance, and gait compared to those of the control group. Conclusion: Vitamin D supplementation improved physiological indices, muscle mass, and physical functions. In addition, this program may help to prevent disorders of the musculoskeletal system in aged women.