Five cases of monostotic fibrous dysplasia involving the spine have previously been reported. We report a sixth case of this entity. The patient had a well-defined lytic lesion with several vertical septations that involved most of the sixth cervical vertebral body with extension to the right pedicle and lamina. Histologic examination revealed fibrous tissue within medullary bone with irregularly shaped bony trabeculae imbedded in the fibrous stroma. Biopsy findings confirmed the diagnosis.