Ankylosing spondylitis is a systemic inflammatory disease, whose pathogenesis is not understood completely, but positive involvement of HLA-B27 markers is observed. Ankylosing Spondylitis can commonly involve the hip joint and cause significant mobility problems. Nonsteroidal anti-inflammatory agents are the first line drugs and they effectively relieve the symptoms. Primary Total Hip Arthroplasty has shown long-term betterment of hip function in patients with ankylosing spondylitis. We report a case of total hip replacement done for hip arthritis secondary to ankylosing spondylitis.