Studies have suggested that Tc-99m white blood cell (WBC) imaging is superior to contrast radiology for assessing the extent and activity of inflammatory bowel disease (IBD). The Tc-99m WBC scan seems ideally suited to obtain, in only one examination, a precise temporal snapshot of the distribution and intensity of inflammation, whereas radiographic methods of investigation tend to represent changes that are more chronic. The test is useful in children with inconspicuous signs suggesting IBD in whom laboratory test results are either normal or slightly abnormal. In those cases, a negative Tc-99m WBC study will obviate endoscopic investigations. The author's current experience, in more than 500 patients, indicates that the Tc-99m WBC scan is a virtual gold standard to establish, or exclude, the diagnosis of IBD. The minimal invasiveness of the Tc-99m WBC scan makes it an especially attractive method for evaluating children with IBD. It is economical compared with endoscopy, and its diagnostic sensitivity is excellent. The ability to evaluate the small and large bowel simultaneously is an important advantage for the patient. In conclusion, the Tc-99m WBC scan is a useful tool to evaluate IBD and should be added to the clinician's investigative armamentarium.