This report summarizes our experience during a four-year period with the repair of 8 thoracic cage and 3 diaphragmatic defects requiring reinforcement with prosthetic material. Defects as large as the entire left hemidiaphragm or the right anterior chest wall including ribs two through six from the midsternum to the midaxillary line were adequately repaired. The technical approach utilized to obtain a secure, nonmobile thoracic cage involved the placement of sutures through drill holes or around ribs, rather than through the periosteum or pericostal soft tissues. Successful diaphragmatic repair was dependent on proper anchoring of the medial border of the prosthesis, placing sutures in the pericardium as necessary. Skin coverage for thoracic cage defects was achieved with widely undermined and advanced local tissue or previously delayed pedicle flaps. All patients had good evidence of chest wall stabilization after operation, and all were removed from mechanical ventilation within three days. One patient died of myocardial infarction twenty days after operation, and a second patient died later of metastatic disease. On the basis of our experience, we conclude that the range of chest wall lesions that can be surgically corrected or palliated is increased by the use of prosthetics implanted with techniques described here.