Hemangioendothelial sarcoma of bone is a rare tumor. A series of 112 cases was studied to define the clinical and pathologic features of this disease. Of the various histologic features evaluated to define the ones most significant prognostically, the histologic grade of the lesions was the single feature that correlated best with disease-free survival. In this series, patients with multi-focal tumors did not have a better prognosis than patients with unicentric disease. Surgery remains the primary treatment for these patients. Radiotherapy may be useful for surgically inaccessible lesions of the axial skeleton. Too few patients have received adjuvant chemotherapy to evaluate its usefulness in this setting.