Osteoarthritis (OA) is one of the most common forms of musculoskeletal disorders and incurs significant economic, social and psychological costs. OA increases in prevalence and also progresses with aging. Clinically OA is characterised by joint pain, crepitus, stiffness after immobility and limitation of movement. Many cases are 'idiopathic' (disease or condition of unknown course or which arises spontaneously), but OA can also be the end result of several other conditions or due to the combination of several other factors. There are various lifestyle factors that increase the risk of developing OA. Preventable or modifiable risk factors include obesity, occupational factors, sports participation, muscle weakness, nutritional factors and hormonal influence. Pharmacological therapies reduce pain and may reduce joint damage. Surgical interventions correct altered biomechanics to prevent OA. For severely damaged joints, partial or total replacement of the joint is possible for all of the large joints that are commonly affected by OA. OA is commonly associated with a limited function that can be improved with a wide variety of rehabilitative interventions: joint specific exercises, physical fitness, physical modalities. Education and self-management are very important to prevent overuse and to use the joints in the most adequate way.