Osteoarthritis consists of a heterogeneous group of disorders that result in articular cartilage degeneration and is diagnosed on the basis of clinical findings. Pathogenesis involves an imbalance between the synthetic and degradative processes that occur in joints. Current interest in the role of cytokines and metalloproteinases may lead to improved treatment of osteoarthritis. For now, management consists of combinations of pharmacologic and nonpharmacologic therapies. A general pharmacologic approach is to begin with acetaminophen and add a low-dose NSAID, nonacetylated salicylate, selective COX-2 inhibitor, or topical capsaicin cream if needed. If pain persists, full-dose NSAID therapy, with the addition of a protective agent in patients at risk for gastrointestinal bleeding, or full-dose COX-2 inhibitor therapy may be tried. Joint injections, irrigation, or arthroscopy may be beneficial in some cases. In patients who continue to have pain and limited function despite these measures, surgical intervention should be considered.