Several cytokines have been identified as critical mediators of chronic inflammation in inflammatory bowel disease (IBD) and biological therapies that target these molecules have been developed during recent years. Thereby, anti-TNF agents have noticeably improved the treatment of patients with IBD in comparison to conventional therapy. Furthermore, initial clinical trials showed promising results with anti-IL-6 and anti-IL-12/IL-23 agents. In addition to these well-known mediators of IBD, various novel cytokines have been described as critical during the pathogenesis of IBD in recent experimental studies and therapeutic targeting of these cytokines could provide new strategies for human disease.