Ankylosing spondylitis (AS) had previously been considered as a chronic disease with little therapeutic options. Non-steroidal anti-inflammatory drugs (NSAIDs) and regular physiotherapy were the only treatment modalities available for patients with AS. The introduction of biologics into clinical practice has substantially broadened the therapeutic armamentarium in AS patients who are refractory to NSAIDs. Remicade (infliximab; Centocor, Inc., USA), a chimeric monoclonal antibody, targets TNF-alpha, and by inhibition of this proinflammatory cytokine, exerts strong clinical improvement of signs and symptoms of AS. In AS, infliximab 5 mg/kg body weight is usually given as an infusion at weeks 0, 2 and 6, and every 6 - 8 weeks thereafter. An improvement of the disease activity by at least 50% is seen in as many as 50% of AS patients treated with infliximab in addition to NSAIDs. Back pain and also peripheral manifestations, such as enthesitic sites and arthritis, improve, and quality of life significantly increases. In addition, elevated acute phase reactants return to normal or low levels, and active inflammatory lesions of the spine as detected by magnetic resonance imaging substantially regress during treatment with infliximab. Clinical improvement occurs during the first 2 weeks of treatment and the clinical response to infliximab, if given continuously, is sustained and long-lasting as follow-up data of ongoing studies show. The short-term benefit/risk ratio of infliximab is clearly in favour of the drug, and it is estimated that at present up to 30% of patients with active AS are in need of this kind of effective treatment.