Ossification of the yellow ligament (OYL) is considered an uncommon cause of syringomyelia, and single case has been described (11). We encountered simply 1 case of syringomyelia associated with cervical OYL out of more than 320 surgically treated syringomyelia cases.The 66-year-old female patient underwent cervical laminoplasty and displayed good postoperative course. Long-standing blockage of CSF circulation is considered one of the main factors for syringomyelia associated with degenerative disease of the cervical spine [2,3,4,5,6,7,10,11,15]. However this speculation warrants further discussion. We therefore obtained more dynamic and objective data using analytical methods described by Marmarou in 1975 [9]. The clinical course of this patient is discussed with reference to the literature and the results of a CSF dynamic study.