Crohn's disease (CD) is a chronic inflammatory disorder which may involve any part of gastrointestinal tract. Chronic inflammation is primarily due to an immunological imbalance between pro- and anti-inflammatory cytokines, and with a defective apoptosis of lamina propria T cells. Amongst the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) seems to play a central role in pathogenesis of CD. Over the last years, increasing knowledge on the pathogenesis of CD together with progresses in bio-technology have led to the development of a number of biological agents targeting specific molecules involved in gut inflammation, most importantly TNF-alpha and its receptors. The aim of this paper is to critically review the rationale and state-of-the art for the use TNF- alpha inhibitors in the treatment of CD.