Purpose: The purpose of this study was to explore the effects of aquatic exercise program on pain, flexibility, grip strength, self-care activities, helplessness in osteoarthritis patients. Methods: This program was carried out three times a week for 6 weeks by 3 groups of patients among 42 patients in regular swimming pool. Data were analysed by paired t-test for pre and post comparison. Results: There were significantly improved in pain flexibility, grip strength, self-care activities and helplessness after the program. However no significant differences were found in fatigue, difficulty of daily living activities and depression. Conclusion: Aquatic program was proved to be an effective nursing intervention to increase the self-care activities flexibility and grip strength, and to decrease pain and helplessness in osteoarthritis patients.