Tumors involving the proximal humerus confront the surgeon with the problem of both eradicating the osseous lesions and restoring shoulder joint function. This problem is magnified because of the biomechanical complexity of the shoulder, its anatomic configuration, and its inherent lack of stabillity. With the increased interest in limb-sparing resection for lesions in the area, efforts are being made to improve the reconstructive techniques. These include leaving a flail shoulder, an being made to improve the reconstructive techniques. These include leaving a flail shoulder, an arthrodesis using intercalery graft between the scapula and the remaining humerus, or if the glenoid is preserved, an arthroplasy. From January 1984 to December 1993, 23 patients with a malignant or locally aggressive bone tumor in the proximal humerus were treated by limb-sparing surgery in Seoul National University Hospital. Histologic diagnosis included osteosarcoma(6), chondrosarcoma(2), Ewing's sarcoma(1), metastatic bone tumor(11), and recurred giant cell tumor(3). Options for reconstruction following limb-sparing resection in our cases were 10 prosthetic arthroplasties, 3 arthrodeses with an living fibula graft, and 10 arthroplasties with intramedullary nailing and cementization. We performed a retrospective analysis in view of tumor eradication and performance status with modified functional evaluation system of Musculoskeletal tumor Society. In 7 cases(74%), good or fair performance status was acquired with average 3.6 years follow-up(6 months-11 years). Each option for reconstruction resulted in relatively good outcome but rather better result was acquired in giant cell tumor and chondrosarcoma. Estimated survival rates by Kaplan-Meier's method, 5 year survival rate was 81% in primary malignant bone tumors(12), 76% in stage ??B malignancies(5) with 4 years and 4 months follow-up. There was no regional recurrence in primary malignant bone tumors but there were three cases in which distant pulmonary metastases were found in follow-up. Complicationss were one soft tissue infection, two nonunions in arthrodesis with a living fibula graft and one dislodgement of prosthesis in prosthetic arthroplasty. In summary, each option for limb-sparing surgery in malignant bone tumor of proximal humerus might result in rather satisfactory outcome in performance and survival rate when effective preoperative and postoperative chemotherapy were performed in adequately selected cases.