Therapeutic options for patients with more severe forms of spondyloarthritis (SpA) have been rather limited in recent decades. There is accumulating evidence that anti-tumor-necrosis-factor (anti-TNF) therapy is highly effective in SpA, especially in ankylosing spondylitis and psoriatic arthritis. The major anti-TNF-alpha agents currently available, infliximab (Remicade(R)) and etanercept (Enbrel(R)), are approved for the treatment of rheumatoid arthritis (RA) in many countries. In ankylosing spondylitis there is an unmet medical need, since there are almost no disease-modifying antirheumatic drugs (DMARDs) available for severely affected patients, especially those with spinal manifestations. Judging from recent data from more than 300 patients with SpA, anti-TNF therapy seems to be even more effective in SpA than in rheumatoid arthritis. However, it remains to be shown whether patients benefit from long-term treatment, whether radiological progression and ankylosis can be stopped and whether long-term biologic therapy is safe.