Arthritis affects around 3 million people in Australia, representing about 15% of the population. Osteoarthritis is the leading cause of pain and disability among the elderly. Osteoarthritis is the third leading cause of life-years lost due to disability. Obesity and joint injury are important potentially modifiable risk factors for the development of osteoarthritis. Obesity is also an important predictor of progression of osteoarthritis. Currently, about 19000 hip and 20000 knee replacements are performed for osteoarthritis in Australia each year. Prevalence of osteoarthritis and the need for total joint replacement surgery are likely to increase because of a combination of increasing risk factors (age, obesity, injury), increasing expectations for improved quality of life, and improved surgical and anaesthetic techniques making surgery possible for more people. Services to provide these cost-effective procedures need to be increased. Primary and secondary prevention programs aimed at reducing obesity, preventing injury and improving rehabilitation and physical activity are urgently required.