Unstable degenerative spondylolisthesis of the cervical spine is very rare. Slip usually occurs at the C3 on C4 or C4 on C5 levels, immediately above a stiff lower cervical spine. There are two clinical patterns: that with neurological involvement causing cervicobrachial pain or myelopathy and that with neck pain alone. The diagnosis can be made by flexion/extension radiography. All of our eight patients had localised fusion, three anterior and five posterior, and all had satisfactory results one to seven years after operation.