Osteoarthritis is a common rheumatologic disorder. It is estimated that 40 million Americans and 70 to 90 percent of persons older than 75 years are affected by osteoarthritis. Although symptoms of osteoarthritis occur earlier in women, the prevalence among men and women is equal. In addition to age, risk factors include joint injury, obesity, and mechanical stress. The diagnosis is largely clinical because radiographic findings do not always correlate with symptoms. Knowledge of the etiology and pathogenesis of the disease process aids in prevention and management. Acetaminophen and nonsteroidal anti-inflammatory medications remain first-line drugs. Agents such as cyclooxygenase-2 inhibitors and sodium hyaluronate joint injections offer new treatment alternatives. Complementary medication use has also increased. Therapeutic goals include minimizing symptoms and improving function.