Purpose: The purpose of this study was to examine the effects of aquatic exercise on joint angle, pain, stiffness and physical fitness in elderly women with osteoarthritis. Methods: Elderly women with osteoarthritis were offered aquatic exercise between October 2014 and December 2014. In experimental groups, patients were included in pre-determined exercise programs 3 times per week for 12 weeks. Eighteen participants were in the experimental group and 18 participants were in the control group. Joint angle and the Korean Western Ontario and McMaster Universities’ Osteoarthritis Index (pain, stiffness, physical function) were measured pre and post aquatic exercise. The study variables were analyzed using x2 test, Fisher’s exact test, Wilcoxon signed rank test, and Wilcoxon rank sum test with the SPSS statistical package. Results: The experimental groups showed statistically significant decreases in left and right joint angle. However there were no differences in pain, stiffness and physical function. Conclusion: After aquatic exercise program, there was no improvement in subjective symptoms for pain however, the objective index of joint angle index showed improvements which supported the positive effects.