The experience of the authors is based on 17 patients 28 to 76 years old. The defect was always too large to be filled by the surrounding tissues. Six resections were on the sternum or the sternum with ribs. In 4 cases there was also a large resection of skin and muscles and in 3 cases pulmonary resection was associated. Prior to 1971 the authors used a crinoplate 3 times, a thin Marlex plate once and a thick one 5 times. Since 1971, 11 prostheses of methyl methacrylate were fixed with a double metal mesh (3 cases) or a Marlex mesh (8 cases). The authors insist on the interest of the latter prosthesis, made concurrently, easily and solidly fixed, and immediately and indefinitely well tolerated. In cases of large resections of muscle and skin the greater omentum can be used as described by Kiricuta to protect skin flaps from the plate prosthesis.