Infliximab is arguably the first major advance in therapy for inflammatory bowel disease in more than a quarter of a century. Although it is important to distinguish efficacy from effectiveness, the data from clinical practice mirror those from randomized controlled trials. Infliximab has proven efficacious for luminal manifestations of Crohn's disease (CD) regardless of location. It also has proven efficacy in the subset of penetrating disease to the skin and perianal area, and it increases rates of steroid-free remission. These benefits are reflected in improved quality of life, with limited data showing that infliximab can decrease rates of hospitalization and CD-related surgery. Infliximab also has proven to be efficacious in patients with ulcerative colitis (UC) and has increased rates of steroid-free remission. Whether infliximab will have an impact on the risk of colorectal cancer in UC and Crohn's colitis has yet to be determined. The combination of strong evidence from large randomized controlled trials with substantial examination of use in the practice setting has moved biologic therapy with infliximab from novel to mainstream. In this review, the data for the efficacy of infliximab in controlled trials will be discussed in the context of real world effectiveness.