Intradural extension of a sacrococcygeal teratoma (SCT) is extremely rare and only well-documented in presacral tumors that have been associated with a familial history, anorectal stenosis, and sacral dysraphism. This case documents the extension of a type I SCT into the dural sac with attachment to the filum terminale. A full-term female was transferred to our tertiary newborn intensive care unit with a sacral mass measuring 12 x 13 cm. It protruded from the buttocks and displaced the anus anteriorly. Rectal examination showed no presacral component. Radiographs demonstrated calcification in the soft tissue mass and a normal-appearing sacrum with the last sacral segment not visualized. At operation during dissection of the cephalad component, the SCT extended into the spinal canal. Neurosurgical consultation resulted in a sacral laminectomy which revealed the tumor to be attached to the tip of the filum terminale. The tumor was removed in toto with all sacral roots preserved. The infant required a second operation to revise a wound dehiscence and suspected cerebrospinal fluid leak. The final pathology report was benign SCT. Follow-up at 2 years showed no recurrence, normal sphincter tone, and a normal computed tomography scan. This represents the first well-documented intradural extension of a Type I SCT with attachment to the spinal cord. This extremely rare occurrence requires awareness with the availability of neurosurgical support to expedite operative management.