Ankylosing spondylitis is a rheumatic disease in which mainly the spinal and sacroiliac joints are affected. Patients with ankylosing spondylitis are at significant risk for spinal fracture when exposed to even minor trauma. Most spinal fractures with ankylosing spondylitis occur in the cervical spine, whereas spinal fractures in thoracic or lumbar spine are rare, especially in the lower lumbar spine. Furthermore, neurologic symptoms in cases of lower lumbar spine fracture are rarer than in cases of cervical and thoracic spinal fracture. We have experienced a case of translation injury of the 3rd lumbar vertebra accompanied by incomplete cauda equine syndrome in ankylosing spondylitis and the authors gained good clinical results with surgical treatment. We have reported here on this case and have included a review of the relevant literature.