Cauda equina syndrome in small animals is a commonly encountered and well described clinical entity. Large breed dogs are more often affected than small breed dogs or cats. The single most important cause of cauda equina syndrome is DLSS, and predominantly affects non-chondrodystrophic large breed dogs. Clinical signs in DLSS result from compression of the cauda equina, or of the nerve roots of the lumbosacral disc combined with disc herniation, as well as hypertrophic degenerative changes of the articular process joints, ligaments and vertebrae. This chapters looks at indications; radiography; normal anatomy; contrast studies; alternative imaging techniques and abnormal imaging findings.