Diffuse idiopathic skeletal hyperostosis (DISH), which is also known as Forestier's disease, is an idiopathic rheumatological abnormality in which extensive ossification occurs along the ligaments throughout the body, most notably in the anterior longitudinal ligament of the spine, and frequently in the posterior longitudinal ligament or ligamentum flavum. Ossification of the ligamentum flavum (OLF) causes narrowing of the spinal canal and cord compression. Radiculopathy, myelopathy or combined neurological alterations can be elicited as a result of ossification. We performed a long-term follow-up of a case progressive myelopathy caused by nodular ossification of the ligamentum flavum in a patient with DISH, who was treated with a posterior decompressive laminectomy and the removal of the ossified ligamentum flavum.