Osteoarthritis is a common chronic, progressive degenerative disorder with a worldwide distribution. Approximately 70 percent of people over 70 years suffer from osteoarthritis. It is a major cause of disability and gradual loss of function. The symptoms of osteoarthritis such as pain, stiffness, fatigue, and negative idea about self-image make the patients avoid exercise, which leads to the development of muscle weakness, joint contracture and deformity. To avoid this vicious cycle, exercise is most important in the treatment of osteoarthritis. Exercise has proved to improve general health and mood, to reduce disability and fatigue, and to modify risk factors. Exercise for patients with osteoarthritis is composed of strengthening exercise, flexibility exercise, aerobic exercise, and proprioceptive training(including balance training). An appropriate exercise program tailored to the individual fitness(muscle strength, flexibility, and endurance) and goals should be stressed in the management of osteoarthritis.