Ankylosing spondylitis (AS) is a chronic inflammatory disease that mainly affects young males and is characterized by inflammatory back pain with sacroileitis and often arthritis of the peripheral joints. To date, no intervention is available that alters the underlying mechanism of inflammation in AS. The purpose of the therapy is to reduce pain and morning stiffness, to prevent deformity, and to maintain correct posture, physical condition, psychosocial health. Nonsteroid anti-inflammatory drugs have been the gold standard in the medical therapy but their effect is regarded as symptomatic rather than curative. The effect of disease modifying antirheumatic drugs is less effective compared with other rheumatic disease such as rheumatoid arthritis. Sulphasalazine, presented recently as a second line drug, has shown some degree of efficacy, particularly in the patients with peripheral arthritis. Methotrexate was reported to be beneficial in AS in open studies, but this could not be confirmed in controlled trials. Biological agents are emerging as drugs that for the first time may provide more than just symptomatic relief to patients with AS. Anti tumour necrosis factor a (anti-TNF a) therapies, infliximab and etanercept, target the specific inflammatory processes of the disease. In placebo controlled trials, treatment with these agents resulted in rapid and significant improvement in clinic and laboratory parameters. Placebo controlled trials are still in progress to detect the long term effects and side effects of anti-TNF a  therapies.