Serologic and fecal biomarkers can be used in the diagnosis and management of inflammatory bowel disease (IBD). Antibodies against Saccharomyces cerevisiae and perinuclear antineutrophil cytoplasmic proteins have been used in diagnosis of IBD, to distinguish Crohn's disease from ulcerative colitis, and to predict the risk of complications of Crohn's disease. C-reactive protein has been used to assess inflammatory processes and predict the course of IBD progression. Fecal markers have been studied for their ability to identify patients with IBD, assess disease activity, and predict relapse. We recently reported that oligosaccharides in IgG and leucin rich alpha 2-glycoprotein are potential biomarkers of IBD. This review addresses the potential for biomarkers to improve treatment strategies and challenges to their use.