Impingement into the coracoacromiohumeral space, a common cause of rotator cuff tendinopathy, may result from an impinging osteoligamentous upper boundary, abnormalities in the tendon itself, or failure of muscles that retain the humeral head on the glenoid. An overuse mechanism is clearly a risk factor in throwing athletes, whereas occupational overuse may contribute to its development in nonathletes. The subacromial anesthetic injection test remains as the acknowledged gold standard for diagnosis. There is evidence on the therapeutic efficacy of nonsteroidal antiinflammatory drugs, glucocorticoid subacromial injection, and acupuncture as compared with placebo. Also, acromioplasty appears to be better than physiotherapy. Patients with rotator cuff tendinopathy may be successfully treated with nonsteroidal antiinflammatory drugs, a glucocorticoid subacromial injection, or acupuncture. In failures of conservative therapy, surgery should be considered. Further research is required on etiology, diagnosis, natural course, and validity of many treatments currently used in this common condition.