The case of a 63-year-old man who presented with Brown-Sequard syndrome plus posterior column deficits due to extensive ossification of the posterior longitudinal ligament is reported. Diagnostic evaluation included magnetic resonance imaging in addition to conventional techniques. The patient was surgically treated by corpectomy and fusion using an anterior approach and made a complete recovery. The occurrence of ossified posterior longitudinal ligament and the diagnostic features are briefly reviewed. With more widespread awareness of this entity and more frequent use of magnetic resonance imaging. we believe more cases will be diagnosed.