Modular endoprosthetic replacement of the upper extremity is an accepted technique following tumor resection. It may also be used in patients who have sustained extensive bone loss about the shoulder girdle because of failed allograft reconstruction, revision of failed arthroplasty, or massive trauma. This article reviews the indications, surgical techniques, and results of endoprosthetic replacement of the proximal humerus and scapula. Soft-tissue reconstruction techniques which are essential for stability and designed to optimize functional outcome, will be discussed