Our goal was to evaluate the objective and subjective midterm outcome after revision of a failed shoulder arthroplasty with a reverse design prosthesis. Twenty consecutive patients with 21 revisions of a primary shoulder arthroplasty using reverse shoulder prosthesis Delta III(®) were followed up postoperatively for a mean of 46 months including clinical and radiological examination. Complications were recorded and Constant score, DASH and SF36 were assessed. With the numbers given a significant reduction of pain was achieved from 8.7 to 3.0 (p < 0.001). There was a significant improvement of active flexion from 43° to 97° (p < 0.001) and active abduction from 44° to 90° (p < 0.001). However, at the same time, active external rotation with an adducted humerus decreased significantly from 26° to 12° (p = 0.012). The constant score improved significantly from 16.7 to 55.9 (p < 0.001). Sixteen patients (84%) rated their shoulder better or much better than before. In 43% an intraoperative and in 38% a postoperative complication occurred including two late stage infections which required prosthesis removal. Our results support the use of the reverse prosthesis as revision prosthesis. The reverse design helps to compensate functional deficits due to severe soft-tissue damage except active external rotation. Nevertheless, the revision is a technically demanding procedure reflected in a high rate of intraoperative complications. The rate of secondary infections of 10% remains a special concern.