A 34-year-old man presented with angiosarcoma which developed at the site of a preexisting bone infarct in the metaphysis of the right tibia. A malignant bone tumor may develop at the site of bone infarct, and its histologic type is most frequently malignant fibrous histiocytoma or fibrosarcoma. Few patients with osteosarcoma have been reported: only 2 patients who had angiosarcoma that developed in a preexisting bone infarct have been reported in the English literature. Malignant transformation of bone infarct into angiosarcoma is extremely rare.