The introduction in the mid-1990s of tumor necrosis factor (TNF) antagonists changed the treatment of inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis (UC) refractory to conventional medications (corticosteroids, immunomodulators). This review summarizes current data on the long-term efficacy and safety of anti-TNF therapy in IBD beyond 1 year. We searched Medline, the Cochrane Library, Embase, and Ovid Medliner for relevant studies. Infliximab, adalimumab and certolizumab are effective in maintaining clinical remission in luminal Crohn's disease. Infliximab and adalimumab are also effective in maintaining long-term fistula closure in Crohn's disease. Only infliximab has been evaluated in UC in the long term, with similar data on its effectiveness than in CD. In addition to the maintenance of clinical remission, TNF antagonists have the ability to maintain long-term mucosal healing, resulting in a reduced risk of surgery. With 2010 on the horizon, we have no good reasons to stop anti-TNF therapy in IBD patients because of its efficacy in maintaining remission and a risk-benefit ratio that remains in its favor. It is now clear that patients in deep remission, comprising clinical, biological, and endoscopic remission, are at lower risk of relapse after withdrawal of anti-TNF therapy.