A caisson worker with symmetrical bone infarcts in the tibiae demonstrated a malignant transformation of one of the bone infarcts with wide-spread metastases to the lungs and viscera. Histologically, the tumor was found to be a malignant fibrous histiocytoma and despite amputation, the patient died approximately one year following the diagnosis. This case lends credence to the concept of a cause and effect relationship existing between bone infarcts and the subsequent development of bone sarcoma.