Ankylosing spondylitis is a chronic inflammatory disease of unknown etiology that affects spine, sacroiliac joint, and the large joints of the extremities, and lead to fibrous or bony ankylosis and deformity. The rigid ankylosed spine of ankylosing spondylitis is prone to fracture by minimal trauma, and the resulting fractures likely to be unstable and damage to spinal cord or cauda equina. The authors report a case of paraplegia in ankylosing spondylitis after open reduction of the femoral trohanteric fracture.