The authors report a series of 20 patients affected with metastatic lesions of the proximal humerus (19 cases) or scapula (one case) treated by intra-or extra-articular resection of the humerus and successive reconstruction with an I.O.R. type shoulder modular prosthesis. This method is indicated for the treatment of patients with extensive destruction of the epiphysis and cortical bone and limited invasion of the surrounding soft tissues. Prosthetic implant does not contraindicate the use of postoperative radiotherapy, and the cement used to anchor the endomedullary shaft contributes to the sterilization of any metastatic microfoces present by means of an intense esothermic polymerization reaction. The results obtained were satisfactory, with regression of pain and good functional recovery of the limb. There were no postoperative complications.