Ossification of the ligamentum longitudinale posterius is a rare disease found in particular in Japan and southeastern Asia. In the literature it is described as the so-called Japanese disease or OPLL syndrome. The disease takes a slow, frequently asymptomatic, course but may cause severe stenosis of the spinal canal with neurological disorders, OPLL occurs frequently concurrently with ankylosing spondylitis, hypertrophic spondylosis, diffuse idiopathic hyperostosis of the skeleton. Own observation: a 68-year-old man with a long history of cervicalgia, subsequently paraesthesias of the upper extremities, without a spastic atactic symptomatology of the lower extremities. An X-ray extremities, of the skeleton was made, tomograms and CT of the cervical spine. In the Cl-6 area major ossifications of the posterior longitudinal ligament were found which caused stenosis of the spinal canal of an extent of up to two thirds.