Twenty patients with frozen shoulder syndrome treated by hydraulic distension of the glenohumeral joint under local anesthesia are reported. All patients were followed for six months to ten years. Subjective complaints included pain, sleep loss, and limited shoulder motion, which compromised daily activities. Objective findings included decreased intracapsular volume; decreased glenohumeral motion, particularly internal and external rotation; and exquisite pain on extremes of motion. Hydraulic distension is carried out under local anesthesia. Capsular inflammation in the anterior synovial recess with resulting tenting of the adjacent subscapularis and biceps tendons is involved in the etiology of the frozen shoulder. The advantages of this modality of treatment are that it is safe, has direct and immediate results, and is cost-effective.