Persistent shoulder pain is a very common condition that often has a multifactorial underlying pathology and is associated with high societal cost and patient burden. In 2000, the direct costs for the treatment of shoulder dysfunction in the United States totaled $7 billion. Persistent shoulder pain can result from bursitis, tendinitis, rotator cuff tear, adhesive capsulitis, impingement syndrome, avascular necrosis, glenohumeral osteoarthritis (OA), and other causes of degenerative joint disease or from traumatic injury, either in combination or as a separate entity. Rotator cuff disorders, adhesive capsulitis, and glenohumeral OA are all common causes of persistent shoulder pain, accounting for about 10%, 6%, and 2% to 5%, respectively, of all shoulder pain. All 3 conditions have complex etiologies, but they can be diagnosed in the majority of patients on the basis of medical history, focused physical examination, and plain film radiographs. This brief review and the following articles in this supplement focus on persistent shoulder pain associated with rotator cuff disorders, adhesive capsulitis, and glenohumeral OA.