A loss of motion after an operation on the shoulder often cannot be treated successfully with physical therapy or closed manipulation. Although open release techniques generally improve motion, they involve extensive dissection. We developed a technique of arthroscopic capsular release and applied it in eighteen patients who had postoperative stiffness of the shoulder. The patients were selected for the arthroscopic release technique if a conservative program of physical therapy and an attempted closed manipulation had failed to restore motion and if they had no known extra-articular contractures. Five of the thirteen patients who had had a global loss of shoulder motion had motion restored with the anterior capsular release, and six needed an additional release of the posterior aspect of the capsule—that is, a combined (anterior and posterior) capsular release. The arthroscopic procedure could not be completed in the remaining two patients because of an extra-articular scar involving the subscapularis, but those patients were managed successfully with an open release. As five patients had lost only internal rotation and flexion, they had only a posterior capsular release.For the eleven patients who had had either an anterior or a combined (anterior and posterior) capsular release, the mean improvement in the score of Constant and Murley was 43 points (range, 31 to 62 points) and all improvements in motion were significant (p < 0.01). Flexion improved a mean of 51 degrees (range, 10 to 65 degrees); external rotation in adduction and abduction, 31 degrees (range, 10 to 50 degrees) and 40 degrees (range, 5 to 80 degrees), respectively; and internal rotation in adduction and abduction, six spinous-process levels (range, three to eleven levels) and 41 degrees (range, 20 to 70 degrees), respectively. For the five patients who had an isolated posterior capsular release, the score of Constant and Murley improved a mean of 20 points (range, 5 to 35 points) and the improvements in motion also were significant (p < 0.05 and 0.005). Internal rotation in adduction and abduction improved a mean of four spinous-process levels (range, one to ten levels) and 42 degrees (range, 30 to 60 degrees), respectively. Eight patients had an arthroscopic acromioplasty for concomitant impingement disease. One patient who had had a combined (anterior and posterior) release and one who had had a posterior capsular release continued to have pain because of injury of the articular cartilage from a previous operation.We concluded that arthroscopic capsular release is a reliable method for restoring motion with minimum morbidity in carefully selected patients who have postoperative stiffness of the shoulder. When necessary, it can be converted to an open release.