Back pain is the well known symptom in ankylosing spondylitis, and is treated with no specific attention except position. Andersson introduced "discovertebral destructive lesions of ankylosing spondylitis" in 1937, and some authors discussed about nonunion and pseudoarthrosis with or without paraplegia after minor trauma, as one of the complications in ankylosing spondylitis. The authors have successfully treated a case of spinal pseudoarthrosis with paraplegia in ankylosing spondylitis, and we think that regular check up in the ankylosing spondylitis patient with aggrevated back pain with or without minor trauma history should be done. So we report it with brief review of literature.