Idiopathic adhesive capsulitis is an enigmatic shoulder disorder that causes pain and reduced range of motion from joint capsule fibrosis. In most cases, the fibrosis resolves and shoulder function returns to normal or near normal. Physicians' major tasks are to differentiate adhesive capsulitis from rotator cuff dysfunction and other causes of shoulder pain and to assist the patient in choosing appropriate treatment. Conservative therapies include rest, analgesia, and range-of-motion exercises. Other treatments include corticosteroid injections, capsular distention, manipulation under anesthesia, and surgical capsular release.