Inflammatory bowel disease, including Crohn's disease and Ulcerative colitis, is a group of conditions characterized by chronic and recurrent systemic inflammatory disorders that primarily affect the gastrointestinal tract. IBD is currently not curable and lifelong management is needed. Thanks to advancements in understanding the mechanisms of IBD, many biological drugs that target specific molecules of the inflammatory cascade of IBD have been developed. Currently, anti-TNF-α biologics, anti-interleukin-12/23/biologics, and anti-integrin biologics are used to treat moderate-to-severe IBD. In this thesis, I describe both available and investigational biologics for IBD.