Experience with 20 cases of chordoma is summarized. Three of four intracranial tumors presented as sellar tumors. The clivus remained intact for 2, 3 1/2, and 4 years, respectively, in three patients despite extensive destructive lesions of the sellar region. Our data and those of others indicate that approximately half the patients with chordomas have erosion of the clivus at the time of initial medical evaluation. The other half mainly have sellar destructive lesions with or without associated clival erosion. Calcification occurs in 50%-70% of intracranial chordomas. A nasopharyngeal mass is present in one-third. Vertebral chordomas often involve two or more vertebrae, producing destructive lesions which often have a sclerotic rim. The intervertebral discs are commonly affected. A paraspinal soft tissue mass, half the time containing calcification, is often present. Sacral lesions are characterized by a midline destructive lesion, occasionally associated with expansion, with or without osteosclerosis. A firm, fixed, extrarectal, presacral mass which may contain calcification or fragments of bone is almost always present.