Purpose: The purpose of this study was to identify the effects of aquatic exercise program on physical fitness, pain and physiological function in patients with osteoarthritis. Method: The subjects of the study were thirty women(age: forty-seventy five) who have an osteoarthritis. Aquatic exercise program consist of approximately two hours of exercise in water, two days per week, for six weeks. Data were gathered from April 19 2005 to May 27 using a questionnaire and measuring physical fitness and physiological index. Data were analyzed with the SPSS Win 12.0 using frequency and paired t-test for difference between pre-exercise and post-exercise. Results: The results of this study were as follows: There were significantly increased on left shoulder (t=3.848, p=.001) and waist flexibility(t=-5.622, p=.001) scores. There were significantly decreased on pain score(t=5.288. p=.000), body weight(t=5.072, p=.001), systolic B.P(t=18.362, p=.001), diastolic B.P(t=32.558, p=.001), blood sugar(t=1.805, p=.041), total cholesterol(t=2.032, p=.026) scores. Conclusion: From these results, it is concluded that the aquatic exercise program can be effective in increasing physical fitness, physiological function and decreasing pain in patients with osteoarthritis.