[en] A case of thoracic myelopathy due to ossification of the ligamentum flavum is presented. A fifty-five year old female complained of sensory and motor disturbance of lower limbs. Neuroradiologically, in addition to ossification of the posterior longitudinal ligament throughout the spines, ossified ligamenta flava were found at the Th10-11 level, and Magnetic Resonance Imaging (MRI) clearly showed the spinal cord compressed at the same level by a low-intensity-signal lesion. Laminectomy and removal of the ossified ligamenta flava improved her neurological dysfunction. The usefulness of the MRI in the neuroradiological diagnosis was confirmed. (orig.)