Although Paget's disease of the spine may cause neurological dysfunction by bone hypertrophy or collapse, it is very rare for the disease process to extend into the soft tissues of the spinal canal. We report a case of Paget's disease causing ossification of the ligamentum flavum and extradural fat, thus causing spinal cord compression. Decompressive laminectomy was carried out, resulting in neurological improvement. In such cases surgical decompression should be followed by therapy with calcitonin.