Chronic pain symptoms cause major medical and socioeconomic problems and are the most common cause of long-term disability in middle aged people. Pain (of various types) is responsible for a half million lost workdays and costs more than $150 billion annually in health care, disability, and related expenses in the U.S. The American Pain Society estimates that 9% of the U.S. adult population suffers from moderate to severe, noncancer related chronic pain. However, epidemiological research has suggested that the prevalence of chronic pain varies, depending on how the survey questions are asked and how chronic pain is defined. Researchers have estimated that from 10 to 20% of adults report having chronic pain when defined as persistent pain lasting at least 3 months. People who are 50 years of age and older are twice as likely to have been diagnosed with chronic pain when compared to people who are younger. Chronic pain management will gain greater public interest as the population ages, and continued research in this field will be an important investment for the future health care of aging Americans. A widely accepted definition of pain was developed by the International Association for the Study of Pain: pain is "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage." There is no single standard taxonomy of pain, but distinctions are frequently made between chronic and acute pain and between cancer and noncancer pain. Chronic pain is generally differentiated from acute pain by its duration, with chronic pain lasting longer than some specified time, often 3 or 6 months. Conditions that cause intermittent recurring pain have characteristics of both chronic and acute pain. There are currently no definitive cures for the most prevalent chronic pain syndromes, such as back pain, peripheral neuropathies, etc. The goal of chronic pain treatment has evolved from eliminating pain to managing pain to an extent that the patient's physical and emotional functioning is restored and overall quality of life improved. This is the model of care provided by the Multidisciplinary Pain Program (MPP). There is no single protocol for treatment provided in MPPs, but there is general agreement on some included methods. In addition, and in contrast to other types of pain treatment clinics, MPPs provide interdisciplinary care: providers from each of the components work together to develop the treatment plan. The definition used in this Technical Brief is based on the presence in the treatment in question of each of four components: medical therapy, behavioral therapy, physical reconditioning, and education. The multiplicity of treatment options has added complexity to health care decisionmaking for patients, providers, and payers. In addition, although there have long been guidelines and consensus opinion documents for treating acute and cancer pain, such guidance on therapy or combination of therapies for managing chronic noncancer pain has been less available. By definition, chronic, noncancer pain has continued past its usefulness-it continues to encourage rest and limits on movement when those limitations impair healing. It persists long enough that the patient may find that side effects and dependence on opioid painkillers limit quality of life. The pain is no longer a signal of new or impending tissue damage-it becomes a disease in itself, sometimes even after the original physical abnormalities are resolved. Chronic pain that continues after the apparent cause is gone is now thought to be a biopsychosocial phenomenon. Though no one knows exactly how the progression happens, it is thought to be influenced by factors such as acute pain intensity, depressive symptoms, and past trauma or stressful life events. When chronic pain does not fully respond to treatment, patients may be referred to a comprehensive treatment program such as an MPP, if one is available.