Osteoarthritis (OA) is highly prevalent and increasing in frequency; the number of patients with OA has increased by nearly 30% over the past 10 years. The primary symptom of OA is pain. Pain and other symptoms of OA may have a profound effect on quality of life (QOL), affecting both physical function and psychological parameters. The economic costs of OA are high, and include those related to treatment, those for individuals and their families who must adapt their lives and homes to the disease, and those due to lost work productivity. These considerable humanistic and economic burdens of OA provide motivation for early identification and treatment. Early diagnosis is assisted by knowledge of risk factors. Classification criteria for OA of the hand, hip, and knee developed by the American College of Rheumatology assist in diagnosis. The European League Against Rheumatism has developed an elaborate system for diagnosis of OA of the hand. Several societies have developed therapeutic guidelines, with general overall agreement between publications. Therapy of OA is multimodal and requires a combination of pharmacologic and nonpharmacologic treatments.