The diagnosis and treatment of pain are among the most challenging problems facing orthopaedic surgeons, and reflex sympathetic dystrophy is probably the most frustrating and difficult pain syndrome to manage. Pain, swelling, and autonomic dysfunction are cardinal signs of the condition. Although the pathogenesis is still unclear, many theories have been proposed. Because reflex sympathetic dystrophy is sympathetically mediated, diagnosis can be confirmed on the basis of response of the pain to sympathetic blockade. Treatment may include an appropriate exercise program, a-adrenergic blocking agents, mood-elevating drugs, calcium channel blockers, intravenous regional blocks, and stellate ganglion blocks. Recent additions to therapy include electroacupuncture, transcutaneous electrical nerve stimulation, and biofeedback. Prognosis is, at best, guarded with this perplexing condition, but the best response is obtained when diagnosis is made early (within the first 2 or 3 weeks after injury) and treatment is initiated during the first stage of the disease.