Over the past several years, significant advances have been made in the diagnostic techniques used in the management of ulcerative colitis and Crohn's disease. These advances have occurred mainly in the area of gastrointestinal endoscopy and radiology. Capsule endoscopy and double-balloon endoscopy have permitted better visualization of the small bowel mucosa. Advanced imaging techniques, including chromoendoscopy, magnification endoscopy, confocal endomicroscopy, and spectroscopy, may aid in the diagnosis of colorectal neoplasia in patients with long-standing disease. Improved radiographic imaging techniques based on computed tomography and magnetic resonance imaging allow noninvasive means of evaluating the small bowel in patients with known or suspected Crohn's disease. Finally, positron emission tomography is an investigative tool for inflammatory bowel disease that may also aid in the detection of inflammation in these diseases.