Tumors of the jaws are epithelial, osseous, or dental in origin. The epithelial tumors, like those of the skin, are epidermal or basal-cell in type, arising from the neighboring mucous membranes or their appendages and invading the jaws by direct extension. The malignant osseous tumors (including osteogenic and Ewing's sarcoma) resemble those of the long bones. The benign bone tumors show features peculiar to this region. The osteomas and ossifying fibromas show a mode of ossification characteristic of membranous bone. The giant-cell tumors may be central or peripheral. The peripheral giant-cell tumors (epulides) are related in their origin to the eruption of the permanent teeth. The dental tumors are usually cystic in character and contain epithelial elements. In their histogenesis they are related to the enamel organ which is derived from the oral ectoderm. The classification and incidence of these tumors of the jaws as recorded in the Surgical Pathological Laboratory at Johns Hopkins, are as follows: