A chordoma is a tumor which arises from remnants or "rests" of the embryonic notochord. It is found almost exclusively in two positions in the body, the clivus Blumenbachii and the sacrococcygeal region. In the latter position the tumor may arise in the sacrum and remain there for the most part, it may grow into the pelvis with the formation of a presacral tumor or it may grow posteriorly, giving rise to a post-sacral tumor. The sites of origin are the notochordal remnants found normally in the nuclei pulposi of the sacrum, and possibly heterotopic foci of chordal tissue anterior or posterior to the sacrum. In this article the clinical manifestations, the surgical treatment and the histopathologic observations in ten new cases of sacrococcygeal chordoma are presented, together with a brief survey of the more important literature. It is interesting that all the earlier cases of chordoma reported occurred in