Inflammatory bowel disease (IBD) is a chronic inflammatory disease that affects the gastrointestinal tract. Information obtained from a clinical history, physical exam, laboratory testing, imaging studies, and endoscopic evaluations must be combined to accurately diagnose IBD. Further testing often becomes necessary to evaluate symptom relapse in patients with an established IBD diagnosis. Endoscopy, while effective in assessing mucosal disease, is invasive and associated with inherent risks. Positron emission tomography (PET) is an effective, noninvasive tool for the evaluation of active inflammation. This review will focus on the role of PET imaging in the evaluation and management of IBD. © 2011 New York Academy of Sciences.